Jerome County, ID — Water Intelligence Brief

October 19, 2026 | Free-Tier Edition

Situation Summary

Jerome County is entering the post-irrigation-season transition, with North Side Canal Company deliveries winding down and dairy operations shifting to year-round groundwater reliance through winter. The critical supply question for Jerome County — upstream reservoir storage in American Falls and Palisades — cannot be answered from publicly available USBR data systems, making direct outreach to IDWR Water District 36 or USBR Pacific Northwest Region the essential next step before any 2027 season planning. Reservoir storage data, 7-day forecast details, and depletion analysis are available in the full brief.

Snowpack Conditions

Lewis Lake Divide (SNOTEL #577, Teton County WY, elev. 7,880 ft)

Current reading (October 18): Snow Water Equivalent 0.0", snow depth 0.0"

Lewis Lake Divide — the upstream Continental Divide station that governs inflow to the upper Snake River, Jackson Lake, Palisades Reservoir, and ultimately American Falls — is reporting no snow on the ground. For this date in mid-October, a 0.0" SWE reading reflects normal seasonal conditions; the historical median SWE at this station is also 0.0" at this point in the calendar. No below-normal language applies to today's reading.

The relevant snowpack context for 2026 is timing, not current depth: Lewis Lake Divide melted out 4–6 weeks ahead of the historical median meltout date, driven by the anomalous March heat wave. That early meltout accelerated runoff into the upper Snake system earlier than typical, compressing the window for reservoir filling. Whether American Falls and Palisades captured adequate storage from that accelerated pulse is the operational question — and it is not answerable from SNOTEL data at this stage of the season. Accumulation at Lewis Lake Divide through November and December will be the first forward-looking signal for the 2027 supply season. Jerome County dairy and alfalfa operators should monitor this station as the primary far-upstream indicator of next season's storage trajectory.

Streamflow Conditions

No active USGS streamflow gauges with current data are available for Jerome County in this brief period. This is a structural monitoring gap: Jerome County has no active in-county USGS gauges relevant to agricultural supply. The county's Snake River supply picture is read through two external reference points — the Snake River at Milner Dam (USGS 13087995, pre-diversion, Twin Falls County) and the Snake River near Twin Falls (USGS 13090500, post-diversion basin integrator) — neither of which is physically located in Jerome County.

No gauge data was provided in this brief's data context. North Side Canal Company operations and any residual Snake River flow at Milner should be confirmed directly with the canal company or IDWR Water District 36. As a standard operational note: near-zero Snake River flow below Milner during active irrigation season is normal — the diversion system is working as designed, capturing essentially the full river for canal delivery. Post-season, below-Milner flows typically begin recovering as diversions wind down.

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. SNOTEL data via NRCS National Water and Climate Center. No USGS gauge data was available for inclusion in this brief period.

Important Disclaimers: This brief provides automated analysis for informational purposes only. Specific numerical claims have not been independently verified. Consult official sources including IDWR Eastern Regional Office (Pocatello, (208) 525-7161); IDWR Water District 36 (Burley office) for Snake River priority administration and reservoir storage data; North Side Canal Company (primary north-bank diverter at Milner Dam, serving approximately 85,000 acres across Jerome, Lincoln, and adjacent counties); A&B Irrigation District (USBR Bureau of Reclamation project serving northern Magic Valley areas in Jerome and Lincoln counties); and U.S. Bureau of Reclamation, Pacific Northwest Region (Boise office) for American Falls and Palisades upstream storage context. American Falls Reservoir and Palisades Reservoir storage data are not available through the USBR RISE API for Idaho facilities — direct contact with USBR or IDWR is required for current figures. This brief does not constitute water rights or legal advice.