State · United States · USGS · BOR · USACE · CDEC
Montana
79.2% average fill
Measured
24
Data pending
1
Volume stored
27,356 hm³
Measured capacity
34,535 hm³
Critical
4
Low level
3
Below month average
16 of 24
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Drought Monitor · 27 October 2026
Weekly map · area in each categoryDrought status
19.2%
of the area in drought (D1 or worse)
Worst category: D3 extreme drought
down 1.3 points on the week
Severe or worse (D2+)
11.4%
Extreme or worse (D3+)
4.9%
DSCI
720–500
People in drought
73,000
Reservoirs (reservoirs.earth)
79.2% full24 tracked
Reservoirs on drought ground
3 of 25
As of the 27 October 2026 U.S. Drought Monitor map, 19.2% of Montana was in drought (D1 or worse), with 4.9% in extreme or exceptional drought (D3–D4). The 24 reservoirs we track in Montana were 79.2% full on their latest readings. 3 of 25 tracked reservoir sites sit inside the drought area.
The Drought Monitor maps where conditions are dry this week — rainfall, soil moisture, streamflow — not how much water is stored. Reservoir storage lags it by months, so a region can be in drought with full reservoirs, or out of drought with empty ones. Source: droughtmonitor.unl.edu. The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration. Map courtesy of NDMC.
Reservoirs
Sorted by capacityFort Peck Dam & Reservoir
Updated 2026-10-28· 96% of month avg
Hungry Horse Reservoir
Updated 2026-10-28· 98% of month avg
Canyon Ferry Lake
Updated 2026-10-27· 99% of month avg
Canyon Ferry Dam & Reservoir
Updated 2026-10-28· 99% of month avg
Bighorn Lake
Updated 2026-10-28· 93% of month avg· D1
Yellowtail Dam & Reservoir
Updated 2026-10-29· 93% of month avg· D1
Lake Elwell
Updated 2026-10-28· 107% of month avg
Tiber Dam & Reservoir
Updated 2026-10-29· 105% of month avg
Clark Canyon Reservoir
lowUpdated 2026-10-28· 79% of month avg
Clark Canyon Dam & Reservoir
lowUpdated 2026-10-29· 80% of month avg
Fresno Reservoir
Updated 2026-10-28· 162% of month avg
Fresno Reservoir
Updated 2026-10-29· 161% of month avg
Gibson Reservoir
criticalUpdated 2026-10-28· 95% of month avg
Nelson Reservoir
Updated 2026-10-28· 97% of month avg
Nelson Reservoir
Updated 2026-10-29· 97% of month avg
Lima Reservoir Upstream of Clark Canyon Reservoir
lowUpdated 2026-10-28· 83% of month avg· D0
Lake Sherburne
criticalUpdated 2026-10-28· 59% of month avg
Lake Sherburne
criticalUpdated 2026-10-29· 61% of month avg
Pishkun Reservoir
Updated 2026-10-28· 69% of month avg
Pishkun Reservoir
Updated 2026-10-29· 68% of month avg
Lake Como
criticalUpdated 2026-10-28· 117% of month avg
Willow Creek Reservoir
Updated 2026-10-28· 182% of month avg
Helena Valley Reservoir
Updated 2026-10-28· 100% of month avg
Bighorn River and BIA Canal near St. Xavier
Updated 2026-10-28· 121% of month avg· D1
Storage from official US gauges (USGS, USACE, Bureau of Reclamation, CDEC) and, in Texas, the Texas Water Development Board. Fill % uses design capacity from the National Inventory of Dams where available; Water Data for Texas lakes use that board's conservation capacity; a few sites without a match fall back to the 5-year maximum. "% of month avg" compares the current fill with the reservoir’s own average for this calendar month over its readings on record. D0–D4 is the U.S. Drought Monitor category of the ground at the reservoir’s coordinates on the latest weekly map — local conditions, not storage.
Major reservoirs — data pending
Lake Frances Reservoir — data sourcing in progress
Storage is monitored by the US Bureau of Reclamation (BOR RISE), but the live feed is currently stale — we are working to restore it. Known capacities: Lake Frances Reservoir (0.1 km³).
About reservoirs in Montana
As of October 29, 2026, the reservoirs we track across Montana that report live levels hold roughly 27,356 hm³ of water — about 79.2% of their combined capacity. Taken together, Montana's reservoirs are within their normal operating range.
Across the region, 4 reservoirs are at critically low levels and 3 are low. Helena Valley Reservoir is the fullest at 87.7%, while Gibson Reservoir is the lowest at 5.8%.
Over the most recent week on record, 4 reservoirs rose and 2 reservoirs fell across Montana.
Storage figures for Montana come from USGS · USACE · BOR · CDEC; the most recent reading is from October 29, 2026. Each reservoir below links to its own page with full history and seasonal context.
Montana at a glance
- Reservoirs tracked
- 24
- Average fill
- 79.2%
- Water stored
- 27,356 hm³
- Combined capacity
- 34,535 hm³
- At critically low levels
- 4
- Fullest
- Helena Valley Reservoir (87.7%)
- Lowest
- Gibson Reservoir (5.8%)
- Last updated
- October 29, 2026