Upper Yellowstone HUC8 10070002
A 7,678 km² sub-basin of the Missouri region in MT, WY. Drought coverage is from the US Drought Monitor (map of 2026-09-01); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
57
Moderate
Drought index
218
Severe
Area in D2+
17.98%
0% exceptional (D4)
Gauges below normal
67%
of 3 reporting
Median flow
78%
p23 of record
Water assets
1,252
82 springs · 216 wells
USGS gauges (4)
- Yellowstone River near Livingston, MT061925001,840 cfsp20 · below normal
- Yellowstone River at Corwin Springs MT061915001,570 cfsp23 · below normal
- Boulder River at Big Timber MT0620000084 cfsp25 · normal
- East Boulder River bl Dry Fork Cr nr Mcleod, MT0619780012 cfsno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 218 | 17.98 | 2/3 | p23 |
Top water assets
- 69Mill Creekriver
- 69Trail Creekriver
- 69West Boulder Riverriver
- 69East Boulder River Bl Dry Fork Cr Nr Mcleod, Mtriver
- 69Eightmile Creekriver
- 69Sweet Grass Creekriver
- 69Yellowstone Riverriver
- 69Trail Creekriver
- 69Otter Creekriver
- 69East Boulder Riverriver