As of mid-May, water levels on both the Crowsnest and Lower Oldman Rivers are seasonally variable, influenced by recent snowmelt and intermittent rainstorms. Mornings typically offer better clarity and lower flow before warming temperatures accelerate runoff in the afternoons. Water temperatures are rising steadily, hovering in the 7–10°C range, bringing increased insect activity and more consistent trout feeding behavior.

Key Flow Considerations:

• Crowsnest River: clearer and more stable due to its spring-fed nature, making it highly fishable even during light runoff.
• Lower Oldman River: can fluctuate more dramatically with rain or snowmelt, especially near mountain inflows. Watch for turbidity after storms or warmer days.
• Wading is generally safe in the mornings, though caution is advised near deeper or faster runs, especially below Waldron Flats on the Oldman.

During the early part of the spring, the water is still cool, and much of the fishing revolves around subsurface presentations. Nymphs, pupae, and larvae are the primary food source for trout, so patterns like Copper Johns, caddis pupa, and stonefly nymphs are often go-tos. The cooler water temperatures slow down the metabolism of the fish, making them more sluggish and less likely to rise to the surface. However, as the water warms and daylight hours lengthen, the rivers will begin to heat up and will trigger the first hatches. From that point on, it should be dry fly heaven.

In terms of hatches that are bumping down south, they will be as follows. Blue-winged Olives (BWOs) begin to emerge, often on overcast days with cooler water temperatures. These mayflies are a significant early-season hatch, and during cloudy afternoons, trout get very keyed into them, rising to sip them off the surface. From there, we should see Caddis. Caddis are one of the most abundant insect families on the rivers, and their emergence has an immediate effect on trout feeding behavior. The trout respond aggressively to the rapid, erratic movements of caddis adults skating across the surface, while their pupal stages become important subsurface food for trout as well. So if you see some explosive eats, there's a good chance they are chowing down on these. But as the month carries on, the most anticipated hatches should start. Those being the Salmon Flies and the Golden Stones. These bugs are not only large and highly visible but also highly sought after by trout. Salmon's, in particular, bring the big boys (and girls) to the surface with dramatic surface takes. The larger sizes of these insects, coupled with their clumsy flight patterns, provide a visual feast for the fish, and it's during these hatches that anglers can often see the most exciting surface action of the season.

As we move through the month, the trout should shift their attention to the stoneflies, and when that happens, there will be no need to fish the small stuff. But for the time being, the best approaches in this neck of the woods are the subsurface strategies. The blue wings are going and the caddis are starting, so using something in their nymphal state as your top fly and then adding a stonefly nymph as your bottom fly would be the best play.

Quick Fact: Although the stonefly hatch once a year they are usually in a body of water for around five years in there nymph form. Because of this they are a constant food source for trout and as we get closer to the back end of May the fish only key into them more.

Streamers will get the job done as well. Using bigger streamers on the lower Oldman would be a great choice, as the bull trout and their predatory nature love to gulp them down. But in the Crow, the best call would be the smaller streamer patterns along the lines of a Sparkle Minnow (size 4-8), Black or Olive Buggers (size 6-10), and the Taupe Leech. Because of the lower flows, adding a split shot to your floating line rig should get the job done. But as the flows begin to rise, it wouldn't be a bad call to change out the floating line for a short(ish) sink tip to better aid in keeping your streamer in the feeding zone.

This is shaping up to be a fantastic spring season for fly fishing in southern Alberta. With consistent hatches on the horizon and fish eager after a long winter, both the Crowsnest and Lower Oldman offer rewarding opportunities for anglers of all experience levels.