USGS Streamgage 12087000
Mashel River near La Grande, WA
Mashel River near La Grande, WA is USGS streamgage 12087000 in Washington, monitoring river discharge in hydrologic subbasin 17110015. It drains a watershed of about 81 square miles. Discharge records at this site go back to 1940. Typical flow runs near 34.3 cfs in July and 249.9 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
- Washington
- Drainage area
- 81 sq mi
- Gauge elevation
- 653 ft
- Subbasin (HUC-8)
- 17110015
- Coordinates
- 46.85674, -122.30259
- USGS site number
- 12087000
- Records begin
- 1940-10-01 (86 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Mashel River near La Grande, WA. 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 |
|---|---|---|---|---|
| 6.6 | 7 | 7.3 | ||
| 6.6 | 7.6 | 10.2 | ||
| 11.4 | 27.2 | 84 | ||
| 14.1 | 30.3 | 63.4 | ||
| 11.7 | 19.9 | 36 | ||
| 9.4 | 13.9 | 22.7 | ||
| 8.1 | 11.2 | 17.4 | ||
| 7.4 | 10.1 | 15.4 | ||
| 7.1 | 9.4 | 13.4 | ||
| 6.7 | 8.8 | 12.1 | ||
| 6.2 | 8.2 | 11.2 | ||
| 6 | 7.8 | 10.5 | ||
| 5.7 | 7.4 | 10 | ||
| 5.5 | 7.2 | 9.6 |
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 86 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 | 104.5 | 275.9 | 921.1 | |
| February | 104.2 | 239.7 | 798.1 | |
| March | 106.8 | 262.6 | 648.5 | |
| April | 127.1 | 249.9 | 506.3 | |
| May | 70.5 | 170.8 | 411.5 | |
| June | 32.1 | 104.7 | 320.1 | |
| July | 13.7 | 34.3 | 93 | |
| August | 7.7 | 15 | 41 | |
| September | 7.2 | 15.4 | 74.3 | |
| October | 12.2 | 51.4 | 255.2 | |
| November | 49.2 | 218 | 716.2 | |
| December | 99.6 | 295.5 | 961.4 |
All values in cubic feet per second (cfs).
Common questions
- When does Mashel River near La Grande, WA normally run highest?
- December, on the long-term record. The median daily flow that month is about 295.5 cfs, against 15 cfs in August, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Mashel River near La Grande, WA?
- It depends on the month. In January, half of days historically fall near 275.9 cfs, with the middle 80% of days between 104.5 and 921.1 cfs. The month-by-month table on this page gives the full range.
- How long has Mashel River near La Grande, WA been measured?
- Discharge records at USGS site 12087000 begin in 1940, about 86 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 Mashel River near La Grande, WA?
- 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 Mashel River near La Grande, WA?
- The gauge sits at 46.85674, -122.30259, in Washington, in hydrologic subbasin 17110015, at an elevation of about 653 feet, draining roughly 81 square miles.
- Can I use Mashel River near La Grande, WA 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.