Minidoka County Water Intelligence Brief

October 19, 2026 | Agricultural Water Management Edition

Situation Summary

Snake River flows at Howells Ferry are running at 420 cfs and falling, signaling a late-season supply environment that demands close coordination with Minidoka Irrigation District and USBR Pacific Northwest Region on Lake Walcott operational status. With the 2026 irrigation season winding down, potato and sugar beet harvest operations are the primary late-season demand, and current falling flows at the county's upstream gauge indicate the Snake River is tracking toward its annual low-flow baseline. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

Lewis Lake Divide (10/18): SWE 0.0", snow depth 0.0".

No snowpack is present at this station, which is the expected seasonal condition for mid-October — the station's historical median SWE for this date is also 0.0", so no below-normal signal is indicated by today's reading. The relevant snowpack context for 2026 is meltout timing: Lewis Lake Divide melted out 4–6 weeks ahead of the historical median meltout date, driven by the anomalous March heat wave that accelerated runoff across the upper Snake River basin. That early meltout front-loaded the 2026 runoff season and is background context for the current low-flow trajectory. Active snowpack accumulation for the 2026–27 season has not yet begun at this elevation.

Streamflow Conditions

Snake River near Minidoka at Howells Ferry (USGS 13081500): 420 cfs, falling (10/19).

Flows at Howells Ferry are in late-season recession, consistent with post-irrigation-season baseflow conditions across the upper Snake River basin. At 420 cfs, the Snake River upstream of Minidoka Dam is well into its low-flow period, with the falling trend indicating continued decline in the near term. This gauge drains approximately 15,700 square miles of upper Snake River watershed and represents the upstream supply signal for the entire Magic Valley corridor — what Howells Ferry shows today is an early indicator of conditions that will register downstream at Milner Dam in subsequent weeks. Minidoka Irrigation District deliveries drawn from Lake Walcott are directly dependent on what this gauge delivers. Current falling conditions reinforce the importance of monitoring Lake Walcott storage directly through USBR Pacific Northwest Region or Minidoka Irrigation District.

Seasonal Guidance

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Data Sources: SNOTEL data through October 18, 2026; USGS streamflow data through October 19, 2026

Data Current As Of: October 19, 2026. Idaho Department of Water Resources, Eastern Regional Office, 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 USBR for American Falls Reservoir and Palisades Reservoir upstream context before making operational or regulatory decisions.