Perfect World
Hydrology Metering

Canyon Ferry Dam · Missouri River · MT

Canyon Ferry Lake

The first big pool on the Missouri, upstream of the Corps' chain.

Water surface elevation

3,787.2 ft

Bureau of Reclamation, daily · daily value, Aug 31

Water in storage

1.56 million acre-feet

Bureau of Reclamation, daily · daily value, Aug 31

Share of capacity

76.2% full

against the project figure capacity figure (USBR Canyon Ferry project data (at el. 3,800 ft))

Below full pool

12.8 ft

full pool at 3,800.0 ft

This month in the record

lower than 75% of the 73 Septembers on record

monthly mean storage; record low 808,660 acre-feet (1953), record high 2.02 million acre-feet (1965)

30-day trend

-3,318 af/day

storage, 2026-07-312026-08-30; over the year +145 af/day. Measured change, not a forecast.

Drought at the dam

none this week

US Drought Monitor at the dam's coordinates, released 2026-08-27; the feeding basin can differ.

full pool 3,800 ftcolumn continues below3,787

76.2% full

of capacity, by storage (project figure figure, USBR Canyon Ferry project data (at el. 3,800 ft)). Sedimentation slowly shrinks real capacity.

The water line is elevation (USBR 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 Missouri headwaters above Canyon Ferry.

Snow season

typically Oct 26 – May 15

0 in on the ground, 2026-09-01; median peak 16.4 in around Apr 26

Last winter's verdict

73% 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 2026-08-31. 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 (USBR RISE, retrieved 2026-08-31).

3786.43789.13791.9May 3Jul 2Aug 303787.2
See the numbers as a table
DateElevation (ft)
Aug 303787.24
Aug 293787.33
Aug 283787.49
Aug 273787.61
Aug 263787.72
Aug 253787.83
Aug 243787.92
Aug 233788.03
Aug 223788.16
Aug 213788.25
Aug 203788.35
Aug 193788.45
Aug 183788.53
Aug 173788.62
Aug 163788.72
Aug 153788.80
Aug 143788.88
Aug 133788.96
Aug 123789.04
Aug 113789.17
Aug 103789.29
Aug 93789.41
Aug 83789.53
Aug 73789.64
Aug 63789.74
Aug 53789.84
Aug 43789.95
Aug 33790.04
Aug 23790.17
Aug 13790.28

Most recent 30 days shown.

The whole record

Monthly mean elevation, Apr 1953 to Aug 2026. The axis spans the pools, not zero; elevations in USBR project datum. Months with fewer than 15 gaged days are dropped, and gaps in the record break the line. Source: USBR RISE, retrieved 2026-08-31.

monthly mean elevationpool reference lines
3,6723,7403,807Apr 1953Dec 1989Aug 2026full pool3,789
See the numbers as a table
MonthMean elevation (ft)Days gaged
Aug 20263788.830
Jul 20263790.931
Jun 20263789.730
May 20263787.331
Apr 20263786.030
Mar 20263783.631
Feb 20263783.628
Jan 20263784.331
Dec 20253783.931
Nov 20253783.130
Oct 20253782.531
Sep 20253783.830
Aug 20253787.431
Jul 20253791.631
Jun 20253793.330
May 20253788.431
Apr 20253784.430
Mar 20253782.931
Feb 20253781.628
Jan 20253783.631
Dec 20243784.231
Nov 20243783.830
Oct 20243783.931
Sep 20243786.130

Most recent 24 months shown; the full monthly series is in the page's API response.

Storage against capacity

Monthly mean storage in acre-feet, zero baseline. The dashed line is the project figure capacity figure (USBR Canyon Ferry project data (at el. 3,800 ft)) — sedimentation slowly shrinks real capacity. Storage can legitimately rise past a conservation-pool line when the flood pool is in use.

monthly mean storagecapacity
01.1M2.2MApr 1953Dec 1989Aug 2026capacity1.6M
See the numbers as a table
MonthMean storage (acre-feet)Days gaged
Aug 20261,612,75630
Jul 20261,681,76831
Jun 20261,643,08930
May 20261,567,21831
Apr 20261,525,24630
Mar 20261,453,75031
Feb 20261,451,77128
Jan 20261,473,79231
Dec 20251,461,49331
Nov 20251,438,91830
Oct 20251,419,53431
Sep 20251,458,50830
Aug 20251,569,84331
Jul 20251,702,71431
Jun 20251,760,45330
May 20251,600,53331
Apr 20251,478,39430
Mar 20251,430,77831
Feb 20251,393,88128
Jan 20251,452,04831
Dec 20241,470,55531
Nov 20241,458,46230
Oct 20241,463,28131
Sep 20241,529,54730

Most recent 24 months shown.

Where these numbers come from

Readings at Canyon Ferry 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 capacity figure is the project figure USBR Canyon Ferry project data (at el. 3,800 ft) number; sedimentation slowly shrinks real capacity, so the vintage travels with the percent.