Marias River Flow Today
As of October 19, 2026 at 1:15 AM, the Marias River is flowing at 515 cfs near Chester Mount, MT — 99% of normal for the date. 3 of 3 USGS gauges reported in the last 3 days; flows range from 271 to 515 cfs. ❤ Favorite
Marias River map
See the Marias River on a live map
Every gauge, dam and paddle run on the river, one tap each:
- Gauges now — which reaches are high or low
- Dams & paddle runs — storage and what’s in range
- Rain — past 24 hrs and the 72-hr forecast, press play
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Marias River conditions today
Where the river is running versus normal, what’s rising or dropping, and what it means for a trip — built from the live USGS readings below.
At Chester Mount, the Marias River is running 515 cfs — 99% of normal. Along the river, 3 of 3 reporting gauges are near normal (the typical gauge is at 99% of normal).
How the Marias River compares to normal
Every reporting gauge from the top of the river to the bottom: bar length is today’s flow, colour is percent of normal for the date.
Flow along the river, upstream to downstream
- Shelby Mount3,099 ft 271 cfs103%
- Chester Mount2,822 ft 515 cfs99%
- Loma Mount2,580 ft 497 cfs97%
Bar length uses a square-root scale so small headwater flows stay visible next to big downstream ones. Colour: <50% 50–90 90–110 110–150 150%+ of normal.
Where every gauge sits
One dot per Marias River streamgauge, placed by its own percent of normal. The line is the typical gauge (99%).
Marias River flow report
| Streamgage | Streamflow | % of normal | 24h | Gage height | To flood stage | Elevation |
|---|---|---|---|---|---|---|
|
Marias River Near Shelby Mount MT
Oct 19, 1:30 AM · USGS 06099500 |
271 cfs | 103% | -7% | 2.83 ft | 6.2 ft below | 3,099 ft |
|
Marias River Near Chester Mount MT
Oct 19, 1:15 AM · USGS 06101500 |
515 cfs | 99% | 0% | 3.43 ft | · | 2,822 ft |
|
Marias River Near Loma Mount MT
Oct 19, 1:15 AM · USGS 06102050 |
497 cfs | 97% | +1% | 1.18 ft | · | 2,580 ft |
USGS provisional data. Readings are in each gauge’s local time; gauges silent for more than 3 days are marked “Last reported”. Tap any gauge for its hydrograph, forecast and history.
Paddle runs on the Marias River
Each run is checked against its runnable range using the gauge it is keyed to (or the nearest gauge on this river).
| Run | Status | Flow now | Runnable range | Class |
|---|---|---|---|---|
| Marias River Gauge: Loma Mount |
No live range | 497 cfs | 48–157 cfs typical | II–III |
Dams & reservoirs on the Marias River
Releases from these dams shape the flow downstream. Tap one for its daily level and history.
Marias River streamflow over time
Daily total flow across every monitored gauge on the river.
Maximum streamflow by year
Marias River
The Marias River is a tributary of the Missouri River, spanning a length of approximately 210 miles in Montana. The river is named after the French explorer, Marias, who first discovered it in 1806. The hydrology of the Marias River includes a snowmelt-dominated flow with high seasonal variability. There are several reservoirs and dams along the river, including Tiber Dam and Lake Elwell, which are primarily used for irrigation and hydroelectric power generation. Recreational activities such as fishing and boating are popular among tourists and locals. Agriculture is also a significant industry along the Marias River, with crops such as wheat, barley, and hay being grown in the area. Despite being a relatively small river, the Marias River has played an essential role in the history and economy of Montana.
About the Marias River
How is the Marias River flowing right now?
As of October 19, 2026, the Marias River is flowing at 515 cfs near Chester Mount, MT, about 99% of normal for the date. Across its 3 USGS gauges, current flows range from 271 to 515 cfs. Every gauge’s live reading is in the table above.
Is the Marias River running high or low?
The typical gauge on the Marias River is at 99% of normal for the date. Above 100% means higher than the historical average for this calendar day; below 100% means lower. The profile above shows which reaches are high or low.
What is flood stage on the Marias River?
The National Weather Service sets flood stages for Shelby Mount (9.0 ft), . The table shows how far each gauge is below its flood stage right now.
Is the Marias River runnable for paddling today?
Each run in the paddle table is checked against its runnable range using its gauge's live flow.
Where does the data come from?
Discharge and gage height are from the USGS National Water Information System; flood stages from the National Weather Service. The history chart sums every monitored gauge on the river.
Can I get alerts for a gauge?
Yes — open any gauge from the table, favorite it in the Snoflo app and set a flow threshold.