Idaho Snowpack & River Runoff

Snow-water equivalent by basin and the seasonal runoff outlook for Idaho's rivers, translated into what it means for fishing — early or late runoff, high or low summer flows, and which waters hold up best. Updated daily through the snow season.

Basin SWE vs. median — water year 2026

Average across the Idaho basins we track, in inches of snow-water equivalent.

12 Idaho rivers tracked

River	Region	Basin snowpack	SWE now / normal	Median melt-out	Runoff forecast
Big Lost River	Central Idaho	—	0.0" / 0.0"	~Jun 7	69%Jun–Jul · 63k acre-ft
Big Wood River	South-Central Idaho	—	0.0" / 0.0"	~Jun 13	62%Jun–Jul · 60k acre-ft
Henry's Fork	Eastern Idaho	—	0.0" / 0.0"	~Jun 4	62%Jun–Jul · 120k acre-ft
Lochsa River	North-Central Idaho	—	0.3" / 0.0"	~Jun 14	55%Jun–Jul · 285k acre-ft
Middle Fork Salmon River	Central Idaho	—	—	—	64%Jun–Jul · 205k acre-ft
North Fork Clearwater River	North-Central Idaho	—	0.1" / 0.0"	~Jun 18	—
North Fork Coeur d'Alene River	Panhandle	—	—	—	53%Jun–Jul · 65k acre-ft
Salmon River	Central Idaho	—	0.0" / 0.0"	~Jun 28	61%Jun–Jul · 1.6M acre-ft
Selway River	North-Central Idaho	—	0.0" / 0.0"	~Jun 2	—
South Fork Snake River	Eastern Idaho	—	0.0" / 0.0"	~May 12	57%Jun–Jul · 995k acre-ft
St. Joe River	Panhandle	—	0.0" / 0.0"	~May 17	58%Jun–Jul · 170k acre-ft
Teton River	Eastern Idaho	—	—	—	56%Jun–Jul · 117k acre-ft

Runoff forecasts are the projected seasonal streamflow volume versus the long-term average, issued monthly January–June. Only rivers with a published forecast point show one.

Snowpack percentages compare current basin snow-water content to historical norms; the Idaho figure is statewide, not specific to any one basin. Snowpack varies with elevation and aspect — treat basin figures as a guide. Updated Jul 16, 2026.

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