As we wrap up June, southern Alberta anglers have experienced a rollercoaster of conditions. Early summer hatches were in full swing, but mid-month brought torrential rains that briefly blew out many rivers. Now, as water levels recede, the Bow River is cleaning up nicely and trout are feeding aggressively again – especially with stonefly season upon us. Below we recap how June fished on the Lower Bow River (Calgary to Carseland) and provide an update on foothills streams in southern Alberta (Highwood, Sheep, Oldman, etc.), which remain elevated and colored from the mid-June rain/snow event.

June started with spring runoff raising the Bow’s flow, but initially it wasn’t as severe or dirty as some years. The river rose from roughly 70 m³/s in early May to around 225 m³/s by mid-June , yet clarity remained decent through these gradual increases. In fact, thanks to a lower mountain snowpack this year, the Bow “never really got high & dirty like years past” during early runoff . Anglers enjoyed consistent fishing on many days despite fluctuating flows – trout were still feeding and could be caught on streamers, nymphs, and even dries whenever the water had a bit of stability . High water often pushed fish tight to the banks, where they remained willing to chase flies presented along the edges .


Everything changed around June 21–22, when a torrential rain storm dumped enormous moisture on the region. Up to 100 mm of rain fell around Calgary with nearly double that in the foothills to the west . This rain-on-snow event in the foothills (where ~10–20 cm of late spring snow also fell at higher elevations) caused a sudden high-water event on the Bow and its tributaries . The Elbow River (which joins the Bow in Calgary) rose rapidly, carrying loads of mud and turning the lower Bow into a chocolate-colored torrent. It appears the foothills snowpack sitting on loose soil contributed to the turbidity – as that snow rapidly melted under heavy rain, it likely picked up tons of sediment. (Such rain-on-snow events are known to cause significant soil erosion and sediment runoff .) In this case the Bow’s downstream tributaries like the Elbow delivered the mud; areas upstream in the mountains got far less precipitation and stayed clearer. The result was a blown-out Bow River from Calgary through Carseland for several days. Many guide trips were canceled for safety and poor visibility, and anglers had to wait it out until flows crested and began to fall.


By the final week of June, the Bow River has stabilized and is recovering quickly. Flows are dropping back toward seasonal levels and water clarity is improving each day. With the river “getting back to normal,” the fishing has bounced back nicely. In fact, lots of bugs were already around during the high water (caddis, mayflies, stoneflies) just waiting for a break in the flows – now the trout can finally see them again! Golden Stoneflies, in particular, are the headline hatch right now. These large summer stoneflies have been popping on the lower Bow for some time, and their emergence is progressing upstream into Calgary . Trout that hunkered down through the muddy spell are now gorging on stoneflies as the hatch intensifies. Anglers are reporting more fish looking up for big dries, especially in sections downstream of the city where the hatch started earlier. Smaller hatches of caddis and PMDs (pale morning duns) are still ongoing each day, but those take a backseat to the big Stoneflies for the moment – the trout know a hefty stonefly is a more filling meal. Early morning and late evening tend to be peak time for stonefly activity (when the adults skitter and lay eggs) , so plan to fish the cool hours if you’re targeting that dry-fly action. During midday, you may see fewer rises, but come late afternoon caddis and PMDs will spur rising fish again near riffles and banks .


For tactics, June’s turbulence reinforced a few lessons. When flows were high and off-color, streamer fishing was the ticket to find aggressive trout hugging the banks. Large, dark streamers (black, olive or brown) produced some terrific fish even in the dirtiest water . Many Bow anglers threw double-streamer setups – for example, a flashy baitfish pattern trailed by a darker bugger or leech – to maximize attraction in the murk . Now that clarity is improving, streamer bites can be more hit-or-miss, but don’t be afraid to keep tossing them, especially under cloud cover. As levels fall, fish will start moving out of the flooded shorelines into riffles and seams again . So, shift your focus back to those spots where sediment is clearing and fish can ambush food.


Dry flies are back in play too. With caddis and mayflies hatching daily, fish are rising most consistently in the afternoons and evenings once the water warms a bit . A tandem dry fly rig can be very effective – for instance, a bushy stonefly or grasshopper pattern as an indicator, with a smaller caddis or PMD dry/emerger tied behind. This covers both the “big bite” and the smaller naturals. If fish are visibly up for stoneflies, you can also skip the dropper and throw a single high-floating foam stonefly imitation. Patterns like Stimulators, Chubby Chernobyls or other golden stone dries are great choices. Just use a stout leader (2X or 3X) to turn over those big bugs and handle fierce strikes. When trout seem picky, downsize to a low-riding stonefly pattern or even try an egg-laying female imitation skittered on the surface – sometimes a subtler presentation draws more eats from pressured fish .


Finally, nymphing remains a reliable fallback on the Bow, especially as it transitions out of runoff. In high water, a big stonefly nymph or dark leech with plenty of weight was crucial to get down in the fast, deep flows . Post-spike, you can lighten up a bit, but you still want to dredge the runs and drop-offs where fish hang mid-column. Fish the “walking pace” water – medium-speed riffles and seams, and adjust your weight/tippet until your flies occasionally tick bottom . Productive nymphs lately include stonefly patterns (Pat’s Rubber Legs, Jimmy Legs, etc.), large prince nymphs, and caddis pupa imitations. With water clarity improving to a few feet, even size 14–16 mayfly nymphs (PMD, pheasant tails) can start to work again for picky feeders.


All in all, June on the Bow tested anglers with big flow swings, but the river is shaping up for excellent summer fishing. The quick surge of runoff helped flush out silt and refresh the system without causing major flood damage – a silver lining. Now we have healthy flows, cooling water, and abundant hatches heading into July. Make sure to check the daily flow rates (as dam releases and weather can change conditions overnight) and approach the river with some flexibility . One day the fish might still hug the banks; the next they could be back in mid-river riffles. By staying adaptable with your flies and tactics, you’ll capitalize on the Bow’s improving conditions. The stage is set for the stonefly extravaganza to continue, backed by caddis at dusk and morning mayfly spinner falls – truly a fun time to fish the Bow!

When the Bow River Rose:

The Flood That Changed a Fishery Calm Before the Storm In mid-June 2013, the Bow River flowed cold and clear through southern Alberta, unsuspecting of the fury that was about to unfold. Snow still clung to the Rocky Mountain peaks; an unusually deep late-season snowpack remained in the high country due to a cool spring and even a late May snowstorm . The day before the flood, river flow levels were unremarkable – around a few hundred cubic metres per second, typical for early summer. Fly fishermen wading the Bow’s gentle runs had no idea that within 48 hours, their beloved river would transform into a raging torrent. It was the calm before a historic storm, with Mother Nature quietly assembling the perfect conditions for disaster: waterlogged ground, lingering mountain snow, and a weather system poised to deliver a deluge. 

The Perfect Storm:

Rain on SnowOn June 19, 2013, dark clouds unleashed a meteorological onslaught over southern Alberta. A stationary high-pressure system to the north forced a moist Pacific low to dump relentless rain on the eastern slopes of the Rockies . In just two days, over 200 mm of rain fell across a vast area – nearly an entire year’s worth of precipitation for this semi-arid region. Some places saw astonishing totals: the town of Canmore recorded 220 mm in 36 hours, and a weather station near High River measured 325 mm in less than 48 hours . Importantly, this wasn’t just rain running off bare ground – it was rain falling on snow. The warm downpour melted the alpine snowpack, turning snow into liquid and multiplying the runoff. The normally thirsty soil was already saturated from prior spring storms, so almost every drop of this rainfall (and melted snow) rushed directly into creeks and rivers. Heavy snow loads remained in the Front Range mountains, so the rain-on-snow effect supercharged the floodwaters . Small mountain streams became brown, boiling rapids overnight. By June 20, tributaries like the Kananaskis, Ghost, Highwood, Sheep, and Elbow were all spilling over their banks . The stage was set for the Bow River – Calgary’s blue-ribbon trout stream – to receive the largest inflow in recorded memory.

Bow River Unleashed:

As the rain pounded down, the Bow River swelled at a rate that defied belief. On the morning of June 20, what had been a fairly placid flow turned into a surging wall of water. In less than 12 hours, the Bow at Calgary rose from roughly 200 m³/s to well over 1,000 m³/s and kept climbing . By the night of June 20, the river had burst over its banks, forcing emergency actions across the region. Authorities issued flood warnings and activated emergency plans as the water raced toward Calgary . On June 21, the Bow River reached its peak flow through the city, gushing at approximately 2,400 m³/s – about eight times its normal rate . (For comparison, this was roughly triple the peak flow of a large 2005 flood a few years prior.) The smaller Elbow River, joining the Bow in downtown Calgary, also exploded to 1,240 m³/s (twelve times its usual flow) , adding to the inundation. Together, these rivers turned low-lying parts of the city into a temporary lake.
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City streets became canals as the Bow River roared through neighbourhoods. Around 80,000 people were urgently evacuated from their homes in Calgary alone , and dozens of communities throughout southern Alberta declared states of emergency . Bridges were overtopped or washed out; power outages plunged parts of the city into darkness. The normally sedate Bow, beloved by anglers for its clear flows, had become a churning, chocolate-brown monster carrying trees, debris, and even pieces of houses in its current. Eyewitnesses along the banks on June 21 described the river as “unrecognizable” – an alien force of nature surging past downtown. At its peak, the Bow ran higher than anyone had seen in several generations, exceeding any flood since 1897 . It was truly a once-in-a-century event, the largest flood in Calgary’s modern history with water levels nearing those of legendary floods from the late 1800s .


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A Region Forever Changed

When the floodwaters finally began to recede after June 22, they left behind a trail of destruction and a landscape forever altered. The 2013 flood was the most costly natural disaster in Canadian history at the time, causing an estimated $5–6 billion in damages across southern Alberta . Whole towns like High River were underwater. In Calgary, 26 neighborhoods were badly flooded . Streets and parks were buried in silt and debris; familiar landmarks were damaged or gone. Tragically, five people lost their lives to the flooding . For those who experienced it, the flood was a life-altering event, a moment when nature’s power humbled an entire region.
For the Bow River itself, the flood was a geomorphic reset. The river scoured its banks and bed with immense force, eroding away entire sections of riverbank and redistributing thousands of tonnes of gravel and sand. Long-time anglers returned to find that their favorite back eddies and side channels simply no longer existed. The river’s architecture was significantly changed – channels shifted, islands and gravel bars moved or disappeared . In Calgary’s iconic Bow River reach, some deep fishing holes were filled in by sediment, while new deep pools were carved elsewhere by the raging current. Tree-lined banks were stripped bare in places, while in other spots the flood deposited new logjams and timber. The Bow’s confluence with smaller tributaries like Fish Creek and the Highwood was completely reshaped by walls of water and debris. It was as if the river had torn up its old blueprint and drawn a new map overnight.

Importantly, not all of these changes were negative for the river’s ecology. While it was heart-wrenching to see beloved river spots altered, floods are a natural process of renewal. Biologists noted that floodwaters, despite wreaking havoc, also created new habitats – for instance, the river carved out fresh side channels and ponds that could become nurseries for juvenile fish . “The changes are all part of the natural process of the river’s own maintenance,” observed Lesley Peterson, a Trout Unlimited biologist, in the months after the deluge . Floods, though destructive, rejuvenate rivers by flushing out accumulated silt, redistributing nutrients, and creating dynamic new environments. In many ways, the Bow River in 2013 was behaving as it always has over centuries – bursting its seams, then gradually healing and finding a new equilibrium. But how would the river’s famous trout fishery fare in the wake of such a cataclysm?



Under the raging floodwaters, the Bow River’s trout were in for the fight of their lives. This river is home to wild populations of brown and rainbow trout (a world-class sport fishery), and these fish had never experienced flows of this magnitude. As the currents sped up and the river volume multiplied, many fish were swept far downstream or into areas they’d never ventured. Some trout likely didn’t survive the violent ride; others were left stranded in atypical places as waters receded. In the days following the flood, observers found live trout flopping in isolated pools and puddles on what had been dry land – side channels and even farmer’s fields that the Bow had temporarily overtaken. The situation looked dire for the fishery. Anecdotal reports suggested a sharp drop in trout numbers, especially rainbow trout, which seemed hardest hit by the flood’s impacts . Rainbows spawn in spring, so the timing was unfortunate – many young rainbow fry may have been simply washed away. Brown trout, which spawn in fall and tend to be a bit larger/older by spring, were thought to have fared slightly better, but they too were displaced and stressed. Long-time fishing guides noted that immediately after the flood, catching trout – especially rainbows – became noticeably more difficult, fueling concern that the Bow’s prized fish population had been decimated.

Yet even amidst this turmoil, there were stories of hope and heroism. As soon as it was safe to approach the river, volunteer crews led by Trout Unlimited Canada (and supported by Alberta biologists and countless local anglers) mobilized for fish rescue operations. They trudged through mud and debris along the Bow’s floodplain, netting stranded trout from residual ponds and channels. Over the week after the flood, these volunteers rescued thousands of fish that would have perished in isolation had they not been returned to the main river . It was an inspiring sight: lines of volunteers passing buckets of wriggling trout, releasing them back into the Bow’s flowing sections. Each rescued fish was a small victory, a sign that the community was determined to help the river recover. “It was heartbreaking and heartwarming at the same time,” one volunteer recounted – heartbreaking to see fish in distress, but heartwarming to see so many people come to their aid. More than 5,000 trout were saved in these efforts , including some trophy-sized browns that had been caught in side ponds. This collective action showed the deep connection Calgarians and Albertans have with the Bow River and its trout – in its darkest hour, they rallied to give back to the river that had given them so much joy.


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Resilience and Recovery:

In the weeks and months after the flood, fisheries biologists kept a close eye on the Bow. They knew that trout populations might take time to rebound, but they were cautiously optimistic. After all, this wasn’t the Bow’s first flood – in 2005, a significant (though smaller) flood hit the river, and data showed that trout numbers bounced back within two years . Rivers and fish are often more resilient than we expect. True to form, by the summer of 2014 there were encouraging signs. Anglers were still catching trout in the Bow, and while catches were lower in some spots, the fish that were caught appeared healthy. Biologists conducting electrofishing surveys observed plenty of young-of-the-year trout in the shallows, indicating that rainbow and brown trout had successfully spawned after the flood and new generations were on the way. In fact, long-term datasets later showed that juvenile trout remained consistently abundant even after 2013 – it was mainly the larger, older trout that had declined in numbers . This meant the building blocks for recovery (the young fish) were in place, as long as they could grow and survive to adulthood.
Over the next few years, the Bow River fishery showed remarkable resilience. Anglers reported that brown trout – which had been almost “unicorns” (rare) immediately after the flood – started to make a strong comeback by 2015 and 2016. Some even noted an increase in large browns, possibly because those hardy fish found refuges during the flood and then had less competition afterward. Rainbow trout numbers, on the other hand, remained a concern. A later scientific analysis confirmed a worrying long-term decline in Bow River rainbows (nearly 50% drop in adult population between 2003 and 2013) . The flood likely contributed to this decline, but it wasn’t the sole factor – other stressors like angling pressure, water management, and the emergence of whirling disease in 2016 also affected the rainbow trout . In response, Alberta’s government and stakeholders launched recovery initiatives, including stricter fishing regulations (the Bow went to catch-and-release only for trout in 2017) and research into cumulative effects on the fishery . These efforts aim to ensure the Bow’s trout have the best chance to thrive in the long run.
Meanwhile, the river itself has healed impressively. The Bow gradually retreated to its pre-flood clarity and flow patterns, albeit in its newly altered channels. Within a year, vegetation started reclaiming the scoured banks; grasses and willows sprouted in the fresh silt deposits, stabilizing the shoreline. Aquatic insects – the mayflies, caddis, and stoneflies so crucial to a trout’s diet – recolonized the gravel beds, and robust hatches resumed, providing a buffet for hungry fish. By 2014 and 2015, anglers could once again witness the evening spectacle of rising trout sipping bugs off the surface. The Bow River, though changed, was very much alive. In fact, some aspects of the fishing even improved: certain runs that had previously been shallow became deeper and more hospitable to fish, yielding surprising new “hot spots” for catching trout. “With the changes in the river, it’s a good opportunity to discover new places to fish along the Bow,” Peterson noted, emphasizing the river’s natural dynamism . Fly-fishers had to adapt to the Bow’s new layout – learning the redesigned riffles, pools, and eddies – but that challenge brought a sense of discovery. The unpredictability of a river is part of its appeal, after all. As Peterson said, “Rivers are naturally dynamic, so to be a good angler you have to work with the river. You can’t expect things to stay the same” . The Bow’s 2013 flood was a dramatic lesson in this truth.

The Bow River Today: A Testament to ResilienceIt’s now been years since that epic flood, and the Bow River has reclaimed its status as one of the world’s great trout streams. If you visit the Bow today, you might hardly guess the violence that once tore through it – except, perhaps, for a newly cut side channel here, or a bank of younger trees there that replaced ones swept away. The river’s trout populations have stabilized and even shown signs of increase in some stretches. Surveys in the downtown Calgary reach still find on the order of 2,500 trout per mile – an astonishing density for an urban river . In the Bow’s classic blue-ribbon section (stretching downstream of Calgary through the prairies), anglers continue to land plump brown trout over 20 inches and feisty rainbows that leap clear of the water. The fish bear a few scars of their trials – one can occasionally spot a healed hook scar on a big rainbow’s jaw, a testament to it having been caught and released multiple times in its life – but they are thriving and wild, descendants of the survivors of 2013. These trout have proven their resilience through floods, droughts, and disease outbreaks. They endure, as long as we safeguard their habitat.
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The legacy of the 2013 flood on the Bow River is twofold. On one hand, it was a sobering reminder of nature’s power, illustrating how quickly decades of human structures (and even some ecological balances) can be upended. It prompted massive investments in flood mitigation and river management to protect communities – new berms, higher dams, floodplains returned to nature – all in hopes of coexisting more safely with the river’s moods. But on the other hand, the flood also highlighted the remarkable resilience of natural systems. Within the chaos was a renewal: the Bow River cleansed and revitalized itself in many ways. Anglers who read the river’s currents today find a mosaic of habitats that likely benefit the ecosystem: deeper holes for fish to hide in during hot summers, newly deposited gravel beds that create spawning grounds for trout and mountain whitefish, and log structures that provide cover. The Bow’s trout, for their part, adapted to the post-flood river and carried on – feeding, growing, spawning the next generation. By 2018, biologists noted strong numbers of young trout, indicating the fishery was replenishing itself despite the setback . Ongoing studies are addressing the remaining challenges (such as ensuring enough big fish survive to older ages), but the river today is still rich with life.

Perhaps most importantly, the 2013 flood instilled a deeper appreciation in the people who know the Bow River. Every time a fly-fisherman steps into the Bow now, there’s a quiet awareness of what the river went through – and a sense of respect. The flood of 2013 made people fall in love with the Bow all over again, in a more profound way: not just as a trout playground, but as a powerful living entity with cycles of wrath and renewal. Anglers swap stories of how their favorite spot “used to be over there before the flood,” then note how they discovered an even better spot later on. There’s a reverence for those trout that survived the flood, and for the river that has carried on.

In the end, the Bow River flood of 2013 was a story of loss and destruction, but also a story of resilience and hope. It changed the river forever – and yet the spirit of the Bow remains. The wild trout still rise eagerly to a well-presented fly on a summer evening, against the backdrop of Calgary’s skyline and the Rocky Mountain sunset. Those trout are living proof that nature can recover when given a chance. As anglers, conservationists, and residents, we are humbled by how quickly things can change, but also encouraged by how well the Bow River has healed. The events of that June will never be forgotten by those who witnessed them. Yet today, when you stand by the Bow and cast your line, you can once again feel that familiar pulse of a healthy river, a river that, despite everything, continues to flow strong and clear, nourishing life and memories for generations to come.

Sources: The factual information and data in this story are supported by official reports and expert observations. Heavy rainfall (200–350 mm) on June 19–21, 2013 combined with alpine snowmelt to trigger the flood . The Bow River’s flow through Calgary peaked around 2,400 m³/s (eight times normal) during the flood , leading to the evacuation of roughly 80,000 people . The flood was the largest since 1897 and caused an estimated $6 billion in damage across southern Alberta . Biologists note that the flood significantly altered river habitat, scouring some areas and creating new ones, but overall fish habitat effects were not entirely negative . Trout Unlimited volunteers rescued thousands of stranded fish from pools as waters receded . Evidence suggests rainbow trout were hit hardest by the flood , though previous floods (like 2005) saw trout populations rebound within a couple of years . In the aftermath, the Bow River remains a productive fishery with about 2,500 trout per mile in the Calgary stretch and a dynamic, resilient ecosystem . The Bow River’s story exemplifies how a wild river and its inhabitants can recover and even thrive after an extreme disturbance, given time and wise stewardship.  

Photo : The Scotiabank Saddledome and surrounding areas in Calgary are submerged by floodwaters on June 21, 2013. Stuart Dryden/Postmedia file

Introduction: The Bow River is entering prime spring fishing mode by mid-May 2025. From Glenmore (Calgary) downstream to the Carseland Weir, anglers are seeing dynamic conditions with rising flows, improving water temperatures, and the first big hatches of the season. In this friendly, up-to-date report, we cover current river conditions, hatch activity, trout behavior, fly recommendations, effective tactics, and access updates. Read on for a comprehensive Bow River fly fishing report that will help you plan your next outing on this world-class fishery.




River Conditions – Flows, Clarity & Temperature



Spring runoff is underway but not yet at full peak. Recent warm weather and rain have started to bump up flows on the Bow River due to flood-control releases at Ghost Dam . Flows have been fluctuating daily – sometimes rising or falling 15–25% within 24 hours – as water managers balance reservoir levels . This means the river might be slightly different each day, so check the latest flow rates on the Alberta Rivers app before you head out. As of mid-May, flow levels are near seasonal norms for spring and trending upward with snowmelt and rain.


Water clarity varies by location. In the upper river through Calgary, the Bow remains fairly clear with a green tint, offering good visibility for trout. However, tributaries like Fish Creek (at Policeman’s Flats) and the Highwood River are adding some color as runoff progresses . The further downstream you go, the more muddy/tea-colored the Bow becomes – by the time you reach McKinnon Flats and below, visibility drops noticeably . In other words, clearest water is near Glenmore and in the city, while below McKinnon Flats the river is more turbid. If you encounter chocolatey water down low, consider moving upstream to find clearer conditions.


Water temperatures are on the rise but still cool in the mornings. Early day water temps linger in the single digits (°C) but warm into the low teens°C by afternoon on sunny days. These warming trends are triggering more bug activity and feeding behavior. Overall, expect typical spring conditions: moderate flows, gradually warming water, and some day-to-day variability if weather swings. Be cautious wading, as flow increases can make for unstable footing – use common sense and wade safely .


Weather outlook: The next two weeks feature a mix of classic spring weather. Daytime highs in the Calgary area are forecast around 13–18°C on average, with a few warmer days in the low 20s and a few cooler, wet days . Several days of light rain and showers are expected through mid to late May, especially around May 14 and May 16-18 . These rains should boost flows slightly and may momentarily reduce clarity, but they’ll also help keep the river in great shape heading into summer. Nights are still chilly (mid single digits), so mornings can start slow until the sun warms things up. Keep an eye on the forecast – a string of warm days or a heavy rain can quickly change river conditions.




Current Hatch Activity – Spring Bugs on the Bow



Spring hatches are popping on the Bow, offering the first consistent dry-fly action of the year. The Blue-Winged Olive (BWO) mayfly hatch is in full swing now. On overcast days especially, large numbers of BWOs can blanket the water . These tiny olive-colored mayflies (size 16–18) are a staple of May afternoons. Trout are starting to look up for them, so mid-day BWO emergences can bring feeding fish to the surface. If the hatch is thick, it can actually be challenging to get bites – fish have so many naturals to choose from. In those cases, anglers have had success using a cripple or emerger pattern (something a bit “mussed up” to stand out) or even a tiny midge cluster to draw attention when trout get picky .


Midges (chironomids) are another prevalent hatch. Clouds of midges have been present on calmer days, and midge shucks are littering boat launches – you could scoop them up by the handful . Trout (and whitefish) are gorging on midge pupae and larvae subsurface. Early in the day or during non-hatch times, bloodworm (midge larva) patterns have been effective, as throat samples showed fish stuffed with red chironomid larvae . Keep an eye out for tiny rises or “sip” rings, especially in slower back eddies, indicating trout taking midges or BWO emergers just in the film.


The famous “Mother’s Day” caddis hatch is just getting started. Anglers have spotted the first few caddis flies (little brown/black sedges) fluttering in the afternoons and evenings . So far, trout haven’t keyed heavily on the caddis adults yet, likely because the hatch is only in its early stage . But this will change quickly as weather warms. In the coming days and weeks, expect caddis hatches to intensify, especially towards evening. You might see splashy rises in the flats at dusk once trout start focusing on caddis. It’s a good idea to have some caddis dry patterns and emergers handy now – you may not need them every day, but when the caddis “pop” you’ll be glad you’re prepared. In the meantime, if you notice caddis adults skittering and no surface takes, try a caddis pupa or emerger pattern subsurface; trout often grab the pupae just below the surface before noticing the adults.


Stoneflies: The early spring stonefly (Skwala) hatch has pretty much wrapped up for the season . A few large dark stonefly adults might still be seen clinging to bankside willows or making the odd appearance on warm afternoons, but they’re no longer a primary food source. Looking ahead, the Golden Stones (the big yellow sallies) are not far off – given the quick snowmelt this year, we could see golden stonefly nymphs migrating and adults emerging earlier than usual, possibly by mid to late June instead of July . For now, trout aren’t really looking up for big stoneflies yet, but an eager angler throwing a size 6–8 stimulator or foam stonefly dry might tempt an opportunistic big brown in the right spot. In any case, keep stonefly nymph patterns in your arsenal – trout will readily gobble them subsurface (more on that below).


Other bugs: Don’t overlook water boatmen – yes, those little backswimmers are present even in spring and can trigger strikes . Some anglers have reported success fishing a small boatman pattern behind a streamer; the erratic, swimming action can provoke explosive takes . Also, as smaller streams in the area report March Browns and lingering Skwala activity, a few of those mayflies and stoneflies could be drifting into the Bow as well (though not in big numbers). The bottom line: the Bow River buffet is expanding. Midges and BWOs are the main course now, with caddis dessert on the horizon and the promise of big stoneflies in early summer.




Trout Behavior – Where Are the Fish Holding?



Springtime trout on the Bow are in transition. A few weeks ago, fish were mostly hunkered down in their winter lies – deep slow pools and troughs – especially early in the day. Now, as flows rise and water warms, trout are spreading out into more typical feeding lanes. You’ll find fish in a mix of spots depending on the time of day and river conditions.


In the mornings or on colder days, many trout still hold in the deeper runs, buckets, and drop-offs where the current is a bit slower near the bottom . These wintering holes remain a safe bet to find fish that haven’t yet started moving much. Nymphing these deep troughs (with ample weight to get down) can produce early-day hookups when the shallow riffles seem lifeless. Whitefish, in particular, are stacked in some deeper seams and readily hit nymph rigs (we’ve seen plenty of 10–14″ whitefish caught on Worms and small nymphs lately) .


By mid-day, especially on sunny afternoons, trout are shifting into softer seams and near structure to feed. As the flows come up, fish seek out comfortable holding water along the banks, on inside river bends, and in softer “frog water” adjacent to faster currents . Current breaks are key – look for trout tucked behind rocks, along shallow shelves, and in front of or behind log jams where they can get out of the main flow. Inside corners (the slower side of a bend) and eddies are prime spots now. In fact, anglers report seeing fish sliding very tight to the banks at times, literally in a foot or two of water right next to shore, especially when the river level bumps up. These edge lies provide shelter from the stronger mid-river current. So don’t ignore the shallow margins – a dry-dropper fished tight to the bank can surprise you with a big brown in skinny water.


Trout still use traditional “feeding lanes” too. If flows are reasonable (not too fast or high), riffles and seam lines that provide food delivery and slightly less current will hold feeding fish. Buckets and tailouts of pools are also productive while spring flows remain moderate . Essentially, the fish are balancing feeding opportunities with conserving energy under variable flows. One tip: when flows fluctuate day-to-day, the fish adjust their positions – on a high flow afternoon they might all be hugging the bank, but after a slight drop in flow they could slide back into mid-river riffles. Be ready to switch locations and tactics during the day as conditions change.


Another notable pattern: Rainbow trout are returning from their spawn in the tributaries, and they’re hungry ! After a spring of spawning, the rainbows re-entering the Bow’s mainstem are looking to put weight back on. These post-spawn rainbows can be aggressive feeders and often less wary than usual. Many anglers are starting to hook into more rainbows each day (in addition to the always-abundant browns). By mid-May the rainbow trout “reunion” is in full effect on the Bow – great news for anglers targeting them. Brown trout, of course, are active as ever. In fact, noted that early season catches were skewed about 4:1 in favor of browns over ‘bows , but that ratio is evening out as rainbows come back. Expect a healthy mix of brown and rainbow trout across all these holding lies. The browns often hold closer to structure or along cutbanks, while rainbows might be more in open seams – but both species are moving around to grab the most food they can.


If you’re keen on streamer fishing or using two-handed rods, note that trout will chase in certain conditions. On sunny days, we’ve seen fish willing to move several feet to intercept a swung fly (trout spey anglers swinging intruder-style streamers had some follows and eats on bright afternoons) . Conversely, when the water dirties up after a flow spike, trout might hunker down and rely more on picking off the occasional meal drifting by their nose. Pay attention to fish behavior – are you seeing flashes near the surface (fish chasing emergers), subtle rise forms (sipping insects), or nothing at all? Adjust your approach to where and how the trout are feeding on that day.


Pro Tip: In late spring, trout often feed hardest during the warmest part of the day (early to mid-afternoon) when water temps peak and insect activity is highest . Morning action can be slow until the water warms enough to get the bugs going . Once that magic temperature (~12°C) is reached, the river can come alive. Plan to fish through the afternoon hatch window, and don’t be in a rush to leave the river early – evening caddis falls or spinner falls can offer bonus dry-fly fishing as the sun gets low.




Fly Selection – Mid-May Fly Recommendations



Spring conditions call for a versatile fly box. You’ll want to be ready for anything from tiny dries to hefty streamers in mid-May. Below are our top fly recommendations by category (dry flies, nymphs, and streamers) for the Bow River right now:




Dry Flies (Surface Patterns)

• Blue-Winged Olive (BWO) Mayfly Patterns: Small olive-bodied mayflies are the hatch du jour, so carry a variety of BWO imitations. Parachute Adams or dedicated Parachute BWO dries in sizes 16–18 are perfect for imitating duns . Also have some BWO emergers or cripples – patterns like a Sparkle Dun or Booty’s BWO Cripple can be deadly when trout refuse the fully emerged duns . On cloudy afternoons when BWOs come off in droves, be ready to match them closely or throw something “different” (like a midge cluster) if trout get selective .
• Midge Adults/Clusters: For those calm moments when trout sip tiny bugs, a Griffith’s Gnat or other midge cluster pattern (size 18–20) is effective. Midges hatch in huge numbers, so sometimes a bushy cluster of midges stands out and draws a strike. Use these if you see fish gently dimpling the surface with no larger mayflies evident.
• Caddis Dry Flies: With caddis beginning to hatch, start packing your favorite caddis patterns. An Elk Hair Caddis in tan or olive (sizes 14–16) works well for the emerging Mother’s Day caddis. For a more exact imitation, try a Peacock Caddis or Bloom’s Parachute Caddis pattern . In the cool early period of this hatch, trout may ignore adults, but as we approach late May you’ll want these ready for evening rises. If fish are swiping at caddis but missing, consider skating your dry or using an emerger trailing behind it.
• Stonefly Dries / Attractor Dries: While not a primary hatch now, a large dark stonefly dry (size 8–10) or a dark stimulator can serve as a great searching pattern . Trout will sometimes hit a big dry this time of year out of opportunism, especially later in the month when they’ve seen a few early stoneflies or even hoppers along the banks. These bigger dries also work well as the indicator fly in a dry-dropper rig (they’re visible and buoyant). A few patterns to consider: Skwala stonefly imitations, foam Chubby Chernobyls in darker colors, or a size 8–10 Stimulator in olive/black. They imitate everything from stoneflies to large terrestrials and can pull up a surprise trout in slower water.

Nymphs (Subsurface Patterns)

• Stonefly Nymphs: Spring is prime time for stonefly nymph fishing. Large Pat’s Rubber Legs (Jimmy Legs) or similar stonefly nymphs in black, olive, or brown are deadly right now . An Excelsior Olive Jimmy Legs or a black/brown girdle bug in size 6–10 makes a great point fly on your nymph rig . Drift these along the bottom in deeper runs and seams – they imitate both the remaining Skwala nymphs and the impending Golden Stone nymphs moving around. Many big Bow River trout eat stonefly nymphs year-round, and in spring they’re a staple meal.
• Mayfly & General Nymphs: With mayflies and midges abundant, smaller sub-surface patterns are extremely effective. Good choices include Bead-head Pheasant Tail nymphs (size 14–18) to match BWO nymphs , and Hare’s Ear nymphs (size 12–16) which suggest a bit of everything . Other productive patterns noted recently are the TJ Hooker (a flashy black stonefly/attractor nymph) and flashback Prince Nymphs . Don’t forget caddis pupa imitations as well – a Green Tungsten Caddis Pupa or Peeking Caddis in size 14–16 can fool trout that are starting to key on emerging caddis. Even if you don’t see adult caddis, trout know the nymphs are active.
• San Juan Worms & Eggs: High or rising flows often dislodge aquatic worms – and San Juan Worms are doing damage on the Bow this spring (especially with a slight stain in the water). Whitefish in particular have been all over pink/red worms , and trout will eat them too when the water is dirty. With runoff beginning, it’s worm time! Similarly, trout are tuned into eggs right now due to the sucker spawn. Rocky Mountain white suckers spawn in spring, spilling eggs that trout feast on. An egg pattern (orange or pink yarn egg) drifted along the bottom can be a sleeper tactic for a big rainbow. Better yet, use an Egg-Sucking Leech fly – this presents both an egg and leech profile. Reports say egg-sucking leech streamers have been excellent recently, both swung and dead-drifted . This pattern does double duty as a nymph or streamer, and it’s working thanks to those eggs in the system.
• Leeches and Wormy Things: Aside from the above, small wooley buggers or leech flies fished under an indicator can imitate leeches or minnows that trout are eating as they wake up from winter. A simple bead-head black leech or peacock leech pattern (size 8–10) was mentioned as a top producer by local anglers . You can fish these like nymphs – trout often take them with gusto, especially in slower pools.

Nymph Rig Tip: Given the mix of bugs, try a two-fly nymph rig pairing a larger fly with a smaller one. For example, a rubberlegs stonefly nymph as your point fly and a small pheasant tail or worm on the dropper. This covers multiple food sources. Keep plenty of split shot handy – getting your nymphs deep enough is critical as flows rise. The fish are often near the bottom (except when feeding on emergers shallow), so ensure your flies are bouncing along the rocks in those faster runs. Strikes can be subtle, so a highly visible indicator or a dry-dropper setup will help you detect takes.




Streamers (Baitfish & Large Patterns)

• Sculpins, Leeches, and Buggers: Streamer time is upon us, especially on days when the water runs a bit murky. Patterns that imitate sculpins and leeches are prime. An olive Woolly Bugger is a perennial favorite and has been producing lately . Other go-to flies include the Bow River Bugger (a local sculpin pattern), black or brown Sex Dungeon streamers, and the Flesh Eating Sculpin (don’t mind the name, it’s deadly) . These bulky patterns push water and grab trout attention. Fish tales from the river suggest that while streamer action has been a bit slower in early May, it’s picking up as runoff progresses . Focus on darker colors or flies with a strong silhouette when the water is dirty, and more natural olive or white tones when the water is clearer.
• Baitfish & Flashy Streamers: As water clarity permits, flashy streamers can shine. Patterns like Clouser Minnows, Kreelex Minnows, or the Silver Lightning Bugger have been effective, especially in the upper clearer stretches . A silver or white minnow pattern fished near structure can entice big predatory browns. One recommended pattern is Eric’s Excalibur or Eric’s Jealousy (local favorites) for their movement and flash . These imitate baitfish and also stand out among the debris in the water. Remember, with bits of sticks and leaves coming downriver during fluctuating flows, sometimes the fly that “stands out from the chaff” is what gets eaten . Don’t be afraid to choose a bright or gaudy streamer in stained water – it can help trout locate your fly amidst everything drifting by.
• Egg-Sucking Leeches & Bunnies: As noted, an Egg-Sucking Leech (black/purple leech with an orange bead head) is doing double duty and has been very successful . Also, bunny leech patterns or zonkers in black, olive, or even white can provoke strikes from larger trout. These flies have great movement; fish them slow and deep.
• How to Fish Streamers Now: With water temps still moderately cool, a slow presentation often works best. Many Bow River trout are hugging banks or resting in slower water, so swinging a streamer down-and-across near the bank can be effective – this lets the fly hover in their face. Anglers have reported success on the swing with longer pauses between strips . You can strip streamers too, but consider a strip-strip-pause cadence to give fish time to react. If one approach isn’t moving fish, change up the retrieve speed or angle. Also, get your streamers deep – use a sink-tip line or add weight so that your fly is near the bottom where the big boys lurk . Streamer fishing may not yield high numbers of fish yet, but the ones you do hook can be tanks. And as the Bow’s flows swell toward runoff, expect the streamer bite to keep improving. Whenever the water is murky or rising, think streamers.

Effective Tactics for Mid-May Trout



Nymphing is the bread-and-butter tactic on the Bow right now.  Reports consistently show that nymph rigs produce the most fish throughout the day . A typical setup might be a 9-foot leader to a strike indicator, with 1–2 split shot, a big stonefly or worm as the first fly, and a smaller nymph trailing 1–2 feet below. Focus on dead-drift presentations with absolutely no drag – the Bow’s trout won’t tolerate a drifting nymph that’s unnaturally speeding up. Make frequent upstream mends to ensure your flies drift naturally at the same pace as the current. When done right, nymphing can hook fish in virtually every type of water: deep pools, riffle seams, and banks. If you’re after numbers or learning the river, nymphing is your best bet to find feeding trout.


Dry-dropper (Hopper-dropper) rigs are another all-star method in spring. This tactic has been producing fish both on the surface and below . Use a bushy dry (large stimulator, foam stonefly, or even a small hopper pattern) as your indicator fly, and tie a nymph 2–4 feet beneath it. Work this rig tight to the banks, through pocket water, and along softer edges. It’s perfect for those fish sitting in 1–3 feet of water near the shore. The dry fly might get the odd eat (we’ve seen some trout nosing up to Skwala or attractor dries lately ), but its main job is to signal strikes on the dropper nymph. Plus, a softly landing dry causes less commotion than a hard indicator, which can be an advantage in clear shallows. Pro tip: Set the hook on ANY slight dip or twitch of that top fly – it’s often a trout subtly eating your nymph.


When bugs are hatching (e.g. a heavy BWO hatch in progress), be ready to switch to a single dry fly and target rising fish. Blind casting dries when nothing is rising usually isn’t effective now (save that for summer), but the moment you see snouts or dimples, take advantage. Identify a rising fish and present your dry fly with a downstream drift if possible (so the fly reaches the fish before your line does). Patience pays off – it’s better to carefully watch a feeding trout and make one good presentation than to cast wildly. Also, don’t be afraid to change flies if a trout refuses your offering. As one guide quipped, if a specific fish refuses you multiple times, try a “Hail Mary” – tie on something completely different (like a midge cluster or even an ant) and see if that triggers a take. Sometimes showing them a contrasting snack amid the hatch can do the trick.


Streamer tactics: As detailed above, slow and deep is a solid plan. Many anglers are having luck swinging streamers down and across in the current – essentially using a wet-fly swing in likely holding water. This is a relaxing and efficient way to cover water: cast at a 45° downstream angle toward the bank, mend once to sink the fly, then let it swing in the current. Watch for a tug or boil behind the fly, and be ready to strip-set. Strip-retrieves are working too, especially with pauses. Try working the head of a pool with a few quick strips and a long pause, then a few more strips. Trout often hit during the pause! If one streamer pattern isn’t moving fish, change size or color before abandoning the technique entirely. A change from an olive bugger to a bright white streamer, for example, can suddenly elicit a chase. Also, when the water visibility is poor, focus your streamer fishing on structure – bang the banks, strip past submerged logs, and work drop-offs, as trout will be tight to those areas.


Adapt to conditions: The Bow’s trout can be moody in spring. One day they’re all about the nymphs, the next they’re ignoring nymphs but slamming streamers or rising to dries. Let the river tell you what to do. For instance, on bright calm days, you might find great dry-fly fishing for BWOs. On a cold front day with gusty winds, the hatch might shut off – that’s when you switch to nymphing deeper or throwing streamers (since wind knocks insects down or prevents hatches) . If the water suddenly colors up after a rain, maybe you stop fishing that size 18 BWO and tie on a worm or flashy nymph that the fish can spot in the murk . Savvy anglers are prepared to change tactics hourly if needed. The most successful anglers recently have been those willing to nymph in the morning, dry-fly fish through a hatch, and then switch to streamers when the afternoon wind muddies the water. Be flexible and you’ll be rewarded.


Finally, don’t overlook the simple things: stealth and presentation. With generally clear spring water (at least in the upper river), trout can see you coming. Try to approach holding areas slowly and low to the ground. Limit wading in shallow spots where fish might be holding. A long leader and fluorocarbon tippet (3X–5X depending on fly size) can help fool those fish in glassy tailouts. And remember to set the hook quickly yet gently – many fish are just “mouth-ing” bugs in the slow water, so if your dry twitches or the indicator pauses, lift the rod. If it’s a snag, no harm; if it’s a fish, you’re on!




Access and Launch Updates (Glenmore, Policeman’s, McKinnon, Carseland)



All the popular access points along the Bow from Glenmore to Carseland are open and ready for anglers as of mid-May. This includes the boat launches and walk-in accesses at Glenmore (below the dam), Policeman’s Flats, McKinnon Flats, and Carseland. After the spring thaw, these launches have been cleared and are being used regularly. In fact, reports confirm that Bow River boat launches are now open – including McKinnon’s Flats which typically is gated in early spring . If you’ve been itching to do the floats (Glenmore to Police, Police to McKinnon, or McKinnon to Carseland), the window is open! Make sure your boat tags and fishing licenses are up to date and enjoy the float season kick-off.


Here are a few notes for each key access:

• Glenmore (Calgary Bow River Upper Launch): This is the put-in right below the Glenmore Dam in Calgary. The reservoir above is at about 55% capacity currently (drawn down for spring) , but that doesn’t affect the downstream launch except that flows can change with dam releases. The path down is clear. No issues reported – anglers are launching drift boats and rafts here to start the float. City construction near the dam has not impacted river access (always check for any City notices, but none are current). Parking is available by the Graves Bridge area. This access gives you the clearest water and a shorter float down to Policeman’s.
• Policeman’s Flats: A very popular spot, both as a take-out (from Glenmore) and as a launch (to float to McKinnon). Policeman’s Flats access is open and the dirt road in is dry for now. Note that with rain in the forecast, that road can get slick – if it’s very wet, use caution driving in/out as it can turn to gumbo mud. The river at Policeman’s is in decent shape; Fish Creek enters just upstream, so water has a slight stain after rain but generally good visibility. No new changes to the parking or launch – it’s the same gravel boat slide and parking area. It can get busy on weekends, so go early to find space. One quirky note: aggressive geese are nesting in the area (common every spring), so give the Canada geese a wide berth when walking to the bank – they will hiss and charge if you get too close to a nest! .
• McKinnon Flats: This is further downstream (accessed off highway 24 east of Calgary). As of May, the McKinnon Flats road and launch are open (the gate is typically opened around May 15, and it’s open now) . The gravel road down the hill to the river is in decent shape – again, avoid it after heavy rain as it can be treacherous when muddy. McKinnon is a common launch for floats down to Carseland (Johnson’s Island) or a take-out from Policeman’s. The river clarity here is usually worse than upstream because the Highwood River enters a few kilometers above McKinnon, bringing in silty runoff . Expect more colored water, especially after rain. Still very fishable, just plan on using maybe bigger, darker flies. McKinnon’s parking area is fine, but there are no facilities (pack out your garbage). This area is more remote – bring bear spray as wildlife roam the river valley.
• Carseland Weir (Johnson’s Island): The end of the line for the Lower Bow float (you must take out above the Carseland weir – going over it is extremely dangerous). The government campground/launch at Johnson’s Island (Carseland) is open. This site often has a concrete boat ramp for take-out. No reported issues; however, always exercise caution approaching the weir. There should be plenty of warning signs and buoys. The take-out is river left before the weir – don’t miss it! If you’re wade-fishing around Carseland, below the weir the river turns into a different fishery (more like a prairie river with different species). But above the weir in the drift stretch, flows and clarity will be similar to McKinnon. No new access restrictions are in place, and the area is fully accessible.

Regulation reminders: The Bow River here is open year-round, but many tributaries are closed until June. Ensure you’re not venturing into any closed waters (for example, the Highwood River is closed until June 16). Be sure to have your 2025 Alberta fishing license – new season licenses became available on April 1, and May Long Weekend anglers need to renew before fishing .


In summary, access points are good to go. Always let someone know your float plan if drifting, and consider the wind forecasts (strong winds can make the row out at Carseland tough). Otherwise, enjoy the great accessibility – you can cover a lot of fantastic water between Glenmore and Carseland with these launch points open.





Conclusion: Mid-May 2025 is an exciting time to be on the Bow River. River conditions are evolving with each passing week of spring: flows are rising but manageable, water clarity is mostly good (with some color downriver), and trout are strapping on the feedbag after a long winter. We have multiple hatches in play – BWO mayflies, midges, and early caddis – giving dry-fly enthusiasts a reason to smile. Meanwhile, nymphing remains highly productive and streamer anglers are finding enough action to keep things interesting. Both brown and rainbow trout are active, with rainbows returning to join the party and big browns prowling the banks. By employing the right flies (as recommended above) and adapting tactics to the day’s conditions, you’ll set yourself up for success.


Remember to stay safe and respectful on the water. Wade carefully in fluctuating flows, keep fish wet and handle them with care, and give fellow anglers space on those popular runs. With all access points open and the river coming to life, it’s a perfect opportunity to get out and enjoy the Bow. Whether you’re floating from Glenmore to Carseland or wading at a favorite spot, you’re in for some fantastic spring fly fishing on the Bow River. Good luck and tight lines!