Twin Falls County Water Intelligence Brief

October 19, 2026 | Agricultural Water Supply Report

Situation Summary

Snake River flows at Milner Dam are reading 0 cfs as of October 19, with 501 cfs recorded at the Twin Falls gauge — indicating that the irrigation season's active diversion window is effectively closing and end-of-season canal operations are underway. For Twin Falls County irrigators, this reflects normal late-October transition conditions: potato harvest is largely complete or wrapping up, and alfalfa cutting has concluded for the season. Upstream storage data for American Falls and Palisades Reservoirs — the key variables governing next season's early-supply outlook — are available in the full brief.

Snowpack Conditions

All three SNOTEL stations in the monitoring network are reporting at or near-zero snow water equivalent as of October 18 — which is entirely normal for mid-October. The median SWE for this date at each station is also 0.0", meaning current readings reflect typical seasonal conditions, not a below-normal snowpack signal.

For context: the 2026 water year was defined by an anomalous March heat wave that drove snowpack meltout 4–6 weeks ahead of the historical median meltout date across the upper basin — a factor that shaped summer Snake River flow trajectories. That story now belongs to the closed 2026 water year. The 2027 snowpack accumulation season is just beginning, and no meaningful signal has yet emerged from the SNOTEL network.

Streamflow Conditions

Two USGS gauges define the Magic Valley flow picture this week:

The 0 cfs at Milner paired with 501 cfs at Twin Falls illustrates the fundamental hydrology of Magic Valley: the canal system diverts the river, and Snake River flows below Milner are largely a function of what the diversion system releases or bypasses.

Seasonal Guidance

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

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

Data Current As Of: October 19, 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.