Minidoka County Water Intelligence Brief

September 21, 2026 | Free-Tier Edition

Situation Summary

Snake River flows at Howells Ferry are running at 3,950 cfs and falling, signaling a late-season supply environment that Minidoka Irrigation District deliveries and upstream storage are now absorbing in full. With harvest demand for potatoes and sugar beets at its seasonal peak, irrigators should confirm current delivery status directly with Minidoka Irrigation District and monitor Howells Ferry trends closely in coming days. Reservoir storage data for Lake Walcott and 7-day forecast details are available in the full brief.

Snowpack Conditions

Lewis Lake Divide, the primary SNOTEL station serving Minidoka County's upstream watershed, is reading 0.0" snow water equivalent and 0.0" snow depth as of September 20. No percent-of-median figure is shown, which reflects normal seasonal conditions — the median SWE for this date is also 0.0". Snowpack is not a current supply variable. The relevant background context is that 2026 snowpack melted out approximately 4–6 weeks ahead of the historical median meltout date, compressing the spring runoff pulse and accelerating the transition to late-season baseflow conditions that are now fully in effect.

Streamflow Conditions

The Snake River near Minidoka at Howells Ferry (USGS 13081500) is flowing at 3,950 cfs with a falling trend as of September 21. This gauge drains approximately 15,700 square miles of upper Snake River basin and represents the upstream supply signal for Minidoka Dam operations and the broader Magic Valley corridor. A falling late-September reading at this location indicates the basin has moved well into recession — runoff contributions are minimal, and flows reflect storage releases and baseflow conditions. Irrigators and Minidoka Irrigation District operations staff should treat current and near-term flows as the effective supply envelope for the remainder of the active irrigation season.

Seasonal Guidance

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

Data Sources: SNOTEL data through September 20, 2026; USGS streamflow data through September 21, 2026

Data Current As Of: Idaho Department of Water Resources (Eastern Regional Office in Pocatello, (208) 525-7161)

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, U.S. Bureau of Reclamation Pacific Northwest Region (Boise office — operates Minidoka Dam and the Minidoka Project, including Lake Walcott), Minidoka Irrigation District (primary delivery entity receiving water from Minidoka Dam diversions), Idaho Department of Water Resources (IDWR — administers Water District 36, middle Snake River), and U.S. Bureau of Reclamation for American Falls Reservoir and Palisades Reservoir upstream context, before making operational or regulatory decisions. This brief does not constitute water rights administration guidance.