Twin Falls County, ID — Water Intelligence Brief

June 11, 2026 | Free-Tier Edition

Situation Summary

The 2026 irrigation season is entering mid-June with snowpack fully melted across all four SNOTEL stations serving the Snake River upper basin — having melted out 4–6 weeks ahead of the historical median meltout date — meaning late-season Snake River flows will depend almost entirely on upstream reservoir releases and Eastern Snake Plain Aquifer conditions rather than continued snowmelt contribution. The Snake River at Milner shows zero cfs at the primary diversion point, while the Twin Falls gauge reflects residual downstream flow, together signaling a supply picture that warrants close coordination with canal companies and IDWR through the remainder of the season. Reservoir storage data for American Falls and Palisades, 7-day forecast details, and late-season depletion context are available in the full brief.

Snowpack Conditions

All four SNOTEL stations monitoring the Snake River upper basin and key tributaries have reached complete meltout as of June 10, 2026:

Because the median SWE for this calendar date at all four stations is also 0.0", these readings reflect normal seasonal conditions for mid-June — not below-normal snowpack today. The meaningful signal for 2026 is timing: meltout occurred 4–6 weeks earlier than the historical median meltout date across the Mountain West, driven by an anomalous March heat wave. Galena Summit, the leading indicator for Big Wood River tributary inflows to the Snake River near the Twin Falls reach, confirms no remaining snowmelt contribution from the Sawtooth Range. The full seasonal snowpack pulse has already passed through the system.

Streamflow Conditions

Two USGS gauges monitor the Snake River through the Magic Valley diversion corridor:

The Milner gauge reading is the most operationally significant data point for Magic Valley irrigators. Milner Diversion Dam — approximately 13 miles upstream of Twin Falls city — is where Twin Falls Canal Company (south bank, ~117,000 acres) and Northside Canal Company (north bank, ~85,000 acres) together divert essentially the full Snake River flow into the approximately 202,000-acre Magic Valley irrigation system. A reading of 0 cfs at Milner indicates that available Snake River flow at the diversion point is at the floor of measurable delivery capacity under current conditions. The 403 cfs reading at the Twin Falls gauge reflects downstream conditions after diversion and tributary contributions — during active irrigation season, the reach below Milner characteristically runs at near-zero as a function of full diversion, which is the defining hydrology of this system. Irrigators and canal operators should monitor both gauges in coordination with Twin Falls Canal Company and Northside Canal Company for current delivery status.

Seasonal Guidance

Subscribe for the full brief including reservoir storage, weather forecasts, depletion analysis, and detailed operational recommendations.

Data Sources: SNOTEL data through June 10, 2026; USGS streamflow data through June 11, 2026

Data Current As Of: June 11, 2026

Important Disclaimers: This brief provides automated analysis for informational purposes only. Specific numerical claims have not been independently verified. Consult official sources including your local water district, Idaho Department of Water Resources (IDWR — administers Water District 36, the middle Snake River priority system), Twin Falls Canal Company (primary south-bank diverter at Milner Dam), Northside Canal Company (primary north-bank diverter at Milner Dam), and U.S. Bureau of Reclamation, Pacific Northwest Region (Boise office — for American Falls Reservoir and Palisades Reservoir upstream context) for regulatory decisions and water rights administration.