Upper Tongue HUC8 10090101
A 6,566 km² sub-basin of the Missouri region in MT, WY. Drought coverage is from the US Drought Monitor (map of 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
39
Stressed
Drought index
299
Severe
Area in D2+
99.42%
0% exceptional (D4)
Gauges below normal
100%
of 2 reporting
Median flow
48%
p9 of record
Water assets
4,192
198 springs · 1,128 wells
USGS gauges (2)
- Tongue River at State Line nr Decker MT06306300118 cfsp7 · much below normal
- Tongue River at Tongue R Dam nr Decker MT0630750098 cfsp11 · below normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-20 | 299 | 99.42 | 2/2 | p9 |
| 2026-10-19 | 299 | 99.42 | 2/2 | p8 |
| 2026-10-18 | 299 | 99.42 | 2/2 | p9 |
| 2026-10-17 | 299 | 99.42 | 2/2 | p8 |
| 2026-10-16 | 299 | 99.42 | 2/2 | p11 |
| 2026-10-15 | 300 | 100 | 1/2 | p22 |
| 2026-10-14 | 300 | 100 | 1/2 | p25 |
| 2026-10-13 | 300 | 100 | 1/2 | p23 |
| 2026-10-12 | 300 | 100 | 1/2 | p18 |
| 2026-10-11 | 300 | 100 | 2/2 | p9 |
| 2026-10-10 | 300 | 100 | 2/2 | p9 |
| 2026-10-09 | 300 | 100 | 2/2 | p9 |
| 2026-10-08 | 246 | 46.49 | 2/2 | p8 |
| 2026-10-07 | 246 | 46.49 | 2/2 | p8 |
Top water assets
- 69Babione Creekriver
- 69South Fork Little Tongue Riverriver
- 69Tongue Riverriver
- 69Little Goose Creekriver
- 69West Fork Big Goose Creekriver
- 69Columbus Creekriver
- 69Rapid Creekriver
- 69Sawmill Creekriver
- 69Prune Creekriver
- 69Trail Creekriver