USGS Streamgage 12389500
Thompson River near Thompson Falls, MT
Thompson River near Thompson Falls, MT is USGS streamgage 12389500 in Montana, monitoring river discharge in hydrologic subbasin 17010213. It drains a watershed of about 638 square miles. Discharge records at this site go back to 1911. Typical flow runs near 343 cfs in July and 640.6 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.
View live conditions & forecast →
Gauge details
- State
- Montana
- Drainage area
- 638 sq mi
- Gauge elevation
- 2,436 ft
- Subbasin (HUC-8)
- 17010213
- Coordinates
- 47.59186, -115.22954
- USGS site number
- 12389500
- Records begin
- 1911-03-01 (115 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Thompson River near Thompson Falls, MT. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.
| Date | Low p10 | Expected p50 | High p90 | Range |
|---|---|---|---|---|
| 151 | 155 | 159 | ||
| 149 | 154 | 158 | ||
| 150 | 157 | 167 | ||
| 150 | 158 | 170 | ||
| 147 | 154 | 162 | ||
| 146 | 153 | 161 | ||
| 144 | 151 | 158 | ||
| 142 | 149 | 156 | ||
| 140 | 147 | 154 | ||
| 139 | 146 | 153 | ||
| 138 | 145 | 152 | ||
| 137 | 144 | 151 | ||
| 136 | 144 | 150 | ||
| 135 | 143 | 150 |
All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 70 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 | 111.7 | 161.4 | 308.1 | |
| February | 117.7 | 175.3 | 406.4 | |
| March | 149.7 | 270.1 | 647.2 | |
| April | 299.2 | 640.6 | 1,388.3 | |
| May | 525.2 | 1,093.5 | 2,209.4 | |
| June | 348.4 | 798.7 | 1,731.3 | |
| July | 186.7 | 343 | 597.6 | |
| August | 132.7 | 215.5 | 308.3 | |
| September | 117.5 | 178.8 | 240.2 | |
| October | 116.5 | 167 | 223.7 | |
| November | 117.9 | 171.6 | 263.5 | |
| December | 108.4 | 163.6 | 301.3 |
All values in cubic feet per second (cfs).
Common questions
- When does Thompson River near Thompson Falls, MT normally run highest?
- May, on the long-term record. The median daily flow that month is about 1,093.5 cfs, against 161.4 cfs in January, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Thompson River near Thompson Falls, MT?
- It depends on the month. In January, half of days historically fall near 161.4 cfs, with the middle 80% of days between 111.7 and 308.1 cfs. The month-by-month table on this page gives the full range.
- How long has Thompson River near Thompson Falls, MT been measured?
- Discharge records at USGS site 12389500 begin in 1911, about 115 years, covering roughly 9,200 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for Thompson River near Thompson Falls, MT?
- Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
- Where is Thompson River near Thompson Falls, MT?
- The gauge sits at 47.59186, -115.22954, in Montana, in hydrologic subbasin 17010213, at an elevation of about 2,436 feet, draining roughly 638 square miles.
- Can I use Thompson River near Thompson Falls, MT data for flood or safety decisions?
- No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.