Flathead River At Columbia Falls
Flathead River · Rockies · USGS gage 12363000
Coldwater (summer mean 13.8°C — prime coldwater; very large river (17,700 cfs)).
Water
54°F
Flow
5,730 cfs
Air
56°F
Sky
0%
Pressure
30.04 in
Wind
4 mph
Predicted hatches · 2026-09-17
PredictedMidgeChironomidae0.30
water 12.4°C (54°F) is cooling past the prime band (1-10°C); shoulder of the season; 8 days sustained ≥0°C; watch midday, especially cold months.
flies: Zebra Midge #18-22, Griffith's Gnat, Disco Midge
PredictedBlue-Winged OliveBaetis spp.0.27
water 12.4°C (54°F) is cooling past the prime band (6-11°C); shoulder of the season; 8 days sustained ≥4°C; watch midday, especially overcast afternoons.
flies: BWO Sparkle Dun #18-22, RS2, Pheasant Tail #18
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.