Water Intelligence Brief · Archive

Caribou County, ID

September 28, 2026

Caribou County, ID — Water Intelligence Brief

September 28, 2026 | Bear River Basin | Free-Tier Edition

Situation Summary

Streamflows across Caribou County's four watersheds are predominantly falling or stable at late-season levels, with the Bear River system trending downward and no snowpack accumulation yet to signal meaningful near-term relief for irrigators approaching the final weeks of the irrigation season. The Portneuf River at Pocatello is a notable exception, showing a rising trend that warrants monitoring for local operational planning. Reservoir storage data and 7-day forecast details for the Bear River and Blackfoot systems are available in the full brief.

Snowpack Conditions

SNOTEL stations across Caribou County's contributing watersheds are uniformly reporting zero or trace snow water equivalent (SWE) as of September 27, consistent with normal seasonal conditions for late September — the historical median SWE for this date at these elevations is also effectively zero, so current readings do not indicate a below-normal snowpack condition for today's date.

Station readings:

  • Bear River RS: SWE 0.0", Depth 0.0"
  • Emigrant Summit: SWE 0.2", Depth 0.0"
  • Franklin Basin: SWE 0.0", Depth 0.0"
  • Garden City Summit: SWE 0.0", Depth 0.0"
  • Giveout: SWE 0.2", Depth 0.0"
  • Slug Creek Divide: Data collection issues — no reading available
  • Tony Grove Lake: SWE 0.0", Depth 0.0"
  • USU Doc Daniel: SWE 0.0", Depth 0.0"

    • The relevant seasonal context is meltout timing: the 2026 snowpack melted out approximately 4–6 weeks ahead of the historical median meltout date, driven by the anomalous March heat wave. That early meltout shaped the summer supply trajectory and is background context for understanding current streamflow levels. The snowpack season for 2026–27 has not yet meaningfully begun. Slug Creek Divide data should be restored through NRCS before the first significant accumulation events — users relying on that station for early-season monitoring should flag the data gap now.

    Streamflow Conditions

    Streamflows across the region reflect typical late-season recession, with most gauges showing falling or stable trends.

    Bear River Basin:

  • Bear River at Border, WY: 57 cfs, falling. This upper-watershed gauge reflects declining late-season inflow entering Idaho from Wyoming.
  • Bear River at Pescadero, ID: 256 cfs, falling. The primary in-state Bear River reference point for Caribou County shows continued late-season decline.
  • Bear River near Corinne, UT: 226 cfs, falling. Downstream terminus gauge confirms the falling trend through the full Bear River corridor.
  • Blacksmith Fork ab Up and L Co.'s Dam nr Hyrum, UT: 47 cfs, stable. A tributary system holding steady at modest late-season flow.
  • Little Bear River at Paradise, UT: 23 cfs, falling. Lower tributary flows continuing seasonal decline.
  • Logan River above State Dam, near Logan, UT: 72 cfs, stable. Holding at a modest late-season level.
  • Malad River near Bear River City, UT: 6 cfs. Note: the most recent reading on this gauge is dated May 15 — this is a stale data point and should not be used for current operational decisions without verification.

    • Blackfoot River Basin:

  • Blackfoot River above Reservoir near Henry, ID: 18 cfs, stable. Low but stable inflow into Blackfoot Reservoir from the upper watershed.

    • Portneuf River Basin:

  • Portneuf River at Pocatello, ID: 105 cfs, rising. This is the standout signal in the current dataset — a rising trend while most other gauges are falling or stable. The source of this rise is not explained by current snowpack or upstream data provided here; users with operational dependence on the Portneuf should seek additional context from IDWR or local water managers.

    • Salt River Basin:

  • Salt River above Reservoir near Etna, WY: 405 cfs, stable. The highest single flow reading in the dataset, reflecting the Salt River system's comparatively robust late-season condition. This gauge is upstream of the Idaho-Wyoming border and provides context for storage inflow rather than direct Caribou County delivery.

    • Seasonal Guidance

  • Contact the Idaho Department of Water Resources Eastern Regional Office (Pocatello, (208) 525-7161) to confirm current Bear River water rights call status and any active curtailment orders affecting your priority date before making late-season diversion decisions.
  • Check with the Bureau of Reclamation Pacific Northwest Region (Boise office) for current Blackfoot Reservoir operational status and projected storage entering the 2026–27 off-season.
  • Contact PacifiCorp and the Bear River Commission for current Bear Lake storage levels, which govern multi-year carryover supply for Bear River basin irrigators across Caribou, Bear Lake, and Franklin counties.
  • Verify your Slug Creek Divide station monitoring plan with the NRCS Idaho Snow Survey office before the first significant early-season snowfall, given the active data collection issue at that station.

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

    Data Sources: SNOTEL data through September 27, 2026; USGS streamflow data through September 28, 2026

    Data Current As Of: September 28, 2026. Water rights and operational status current as of date of publication — conditions may change rapidly during active irrigation season.

    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 (for Blackfoot Reservoir), and PacifiCorp/Bear River Commission (for Bear Lake storage) for regulatory decisions and water rights administration. Idaho Department of Water Resources Eastern Regional Office in Pocatello, (208) 525-7161, for Bear River basin counties.

    Data & Disclaimers

    Sources: NRCS SNOTEL network · USGS National Water Information System · National Weather Service

    This brief provides automated analysis for informational purposes only. Consult official sources including your local water district and state Division of Water Rights for regulatory decisions. This document does not constitute legal, regulatory, or engineering advice.

    Other Issues

    Caribou County Brief — October 26, 2026Caribou County Brief — October 19, 2026Caribou County Brief — October 12, 2026Caribou County Brief — October 5, 2026Caribou County Brief — September 21, 2026Caribou County Brief — September 14, 2026Caribou County Brief — September 7, 2026Caribou County Brief — August 31, 2026Caribou County Brief — August 24, 2026Caribou County Brief — August 17, 2026Caribou County Brief — August 10, 2026Caribou County Brief — August 3, 2026Caribou County Brief — July 27, 2026Caribou County Brief — July 20, 2026Caribou County Brief — July 13, 2026Caribou County Brief — July 6, 2026Caribou County Brief — June 29, 2026Caribou County Brief — June 22, 2026Caribou County Brief — June 15, 2026Caribou County Brief — June 8, 2026Caribou County Brief — June 1, 2026Caribou County Brief — May 26, 2026Caribou County Brief — May 15, 2026Caribou County Brief — April 21, 2026

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