S Fork Flathead River near Columbia Falls
S Fork Flathead River · Rockies · USGS gage 12362500
Coldwater (summer mean 14.9°C — prime coldwater).
Water
49°F
Flow
5,000 cfs
Air
82°F
Sky
44%
Predicted hatches · 2026-06-16
PredictedMidgeChironomidae0.50
Predicted by conditions; no reports yet. water 9.2°C (49°F) sits in 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
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.