Fort Peck Dam · Missouri River · MT
Fort Peck Lake
The oldest and westernmost of the Corps' six Missouri mainstem dams, holding one of the largest pools in the country.
Water surface elevation
2,222.2 ft
US Army Corps, hourly · Sep 30, 10:00 PM MDT
Water in storage
12.48 million acre-feet
US Army Corps, hourly · Sep 29, 11:00 PM MDT
Share of conservation capacity
84.4% full
against the retrieved 2026-09-17 conservation capacity figure (USACE CWMS location level NWDM/FTPK.Stor.Inst.0.Top of Conservation)
Below full pool
27.8 ft
full pool at 2,250.0 ft
This month in the record
lower than 76% of the 59 Octobers on record
monthly mean storage; record low 8.96 million acre-feet (2004), record high 18.22 million acre-feet (1978)
30-day trend
-4,767 af/day
storage, 2026-08-18 → 2026-09-17; over the year -381 af/day. Measured change, not a forecast.
Drought at the dam
D0 — Abnormally dry
US Drought Monitor at the dam's coordinates, released 2026-09-17; the feeding basin can differ.
Flood space left
5.98 million acre-feet
room above today's storage up to the Corps' flood-control ceiling, same total-volume basis
84.4% full
of conservation capacity, by storage (retrieved 2026-09-17 figure, USACE CWMS location level NWDM/FTPK.Stor.Inst.0.Top of Conservation). Sedimentation slowly shrinks real capacity.
The water line is elevation (USACE project datum); the percentage is storage ÷ capacity. They are different measures — a reservoir's volume is not linear in its depth, so the line's height in this column is not the percentage.
Snowpack in the feeding basin
Measured across the upper Missouri ranges — a partial proxy; Fort Peck also drains vast unsnowed plains.
Snow season
typically Oct 26 – May 15
0 in on the ground, 2026-09-29; median peak 20.9 in around Apr 26
Last winter's verdict
82% of median peak
water year 2026 — the snow that fed this year's pool
5 highest active SNOTEL stations in the basin (Boulder Mountain, Elk Peak Alt, Onion Park, …), NRCS AWDB REST (SNOTEL), station set pinned 2026-09-17. Daily snow-water equivalent against the stations' own 30-year medians; off season the percent is withheld rather than divided by zero.
The last 120 days
Daily water-surface elevation in feet. The axis hugs the data — it does not start at zero. Source: committed snapshot (USACE CWMS, retrieved 2026-09-17).
See the numbers as a table
| Date | Elevation (ft) |
|---|---|
| Sep 17 | 2222.78 |
| Sep 16 | 2222.78 |
| Sep 15 | 2222.78 |
| Sep 14 | 2222.78 |
| Sep 13 | 2222.64 |
| Sep 12 | 2222.73 |
| Sep 11 | 2222.77 |
| Sep 10 | 2222.77 |
| Sep 9 | 2222.81 |
| Sep 8 | 2222.85 |
| Sep 7 | 2222.96 |
| Sep 6 | 2222.80 |
| Sep 5 | 2222.87 |
| Sep 4 | 2222.88 |
| Sep 3 | 2222.89 |
| Sep 2 | 2222.91 |
| Sep 1 | 2222.94 |
| Aug 31 | 2222.99 |
| Aug 30 | 2223.01 |
| Aug 29 | 2223.05 |
| Aug 28 | 2223.06 |
| Aug 27 | 2223.07 |
| Aug 26 | 2223.10 |
| Aug 25 | 2223.19 |
| Aug 24 | 2223.28 |
| Aug 23 | 2223.28 |
| Aug 22 | 2223.30 |
| Aug 21 | 2223.33 |
| Aug 20 | 2223.35 |
| Aug 19 | 2223.38 |
Most recent 30 days shown.
Storage against capacity
Monthly mean storage in acre-feet, zero baseline. The dashed line is the retrieved 2026-09-17 conservation capacity figure (USACE CWMS location level NWDM/FTPK.Stor.Inst.0.Top of Conservation) — sedimentation slowly shrinks real capacity. Storage can legitimately rise past a conservation-pool line when the flood pool is in use.
See the numbers as a table
| Month | Mean storage (acre-feet) | Days gaged |
|---|---|---|
| Sep 2026 | 12,580,529 | 17 |
| Aug 2026 | 12,697,323 | 31 |
| Jul 2026 | 12,819,548 | 31 |
| Jun 2026 | 12,729,462 | 26 |
| May 2026 | 12,611,452 | 31 |
| Apr 2026 | 12,548,567 | 30 |
| Mar 2026 | 12,478,742 | 31 |
| Feb 2026 | 12,427,071 | 28 |
| Jan 2026 | 12,423,839 | 31 |
| Dec 2025 | 12,457,290 | 31 |
| Nov 2025 | 12,473,933 | 30 |
| Oct 2025 | 12,495,387 | 31 |
| Sep 2025 | 12,704,900 | 30 |
| Aug 2025 | 13,038,710 | 31 |
| Jul 2025 | 13,258,935 | 31 |
| Jun 2025 | 13,463,933 | 30 |
| May 2025 | 13,497,419 | 31 |
| Apr 2025 | 13,490,233 | 30 |
| Mar 2025 | 13,450,903 | 31 |
| Feb 2025 | 13,145,821 | 28 |
| Jan 2025 | 13,186,871 | 31 |
| Dec 2024 | 13,241,903 | 31 |
| Nov 2024 | 13,314,033 | 30 |
| Oct 2024 | 13,337,097 | 31 |
Most recent 24 months shown.
Where these numbers come from
Readings at Fort Peck Lake are the measuring agencies' own: each value above names its source (USGS gage, Bureau of Reclamation daily record, Army Corps project data, or this desk's committed copy) and its observation time in the reservoir's own time zone. The conservation capacity figure is the retrieved 2026-09-17 USACE CWMS location level NWDM/FTPK.Stor.Inst.0.Top of Conservation number — its basis: top of conservation pool (Corps location level, total-volume basis); sedimentation slowly shrinks real capacity, so the vintage travels with the percent.