USGS Streamgage 12388700
Flathead River at Perma, MT
Flathead River at Perma, MT is USGS streamgage 12388700 in Montana, monitoring river discharge in hydrologic subbasin 17010212. It drains a watershed of about 9,024 square miles. Discharge records at this site go back to 1983. Typical flow runs near 12,518.7 cfs in July and 9,645.3 cfs in April, with the higher of the two arriving in July.
Gauge details
- State
- Montana
- Drainage area
- 9,024 sq mi
- Gauge elevation
- 2,479 ft
- Subbasin (HUC-8)
- 17010212
- Coordinates
- 47.36679, -114.585
- USGS site number
- 12388700
- Records begin
- 1983-10-01 (43 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 42 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 6,665.8 | 9,821 | 13,571 | |
| February | 6,145.2 | 8,855.2 | 14,437.9 | |
| March | 4,763.2 | 8,218.7 | 13,035.5 | |
| April | 4,641.3 | 9,645.3 | 17,460 | |
| May | 8,600 | 15,812.9 | 32,258.1 | |
| June | 12,220 | 22,826.7 | 44,200 | |
| July | 6,826.5 | 12,518.7 | 22,522.6 | |
| August | 4,284.8 | 6,678.1 | 11,527.7 | |
| September | 4,187.7 | 6,322 | 11,128.7 | |
| October | 4,474.2 | 7,532.9 | 11,606.5 | |
| November | 5,268.3 | 9,135.7 | 12,970 | |
| December | 7,637.4 | 10,163.5 | 13,735.5 |
All values in cubic feet per second (cfs).