USGS Streamgage 05018500
St. Mary Canal at St. Mary Crossing near Babb, MT
St. Mary Canal at St. Mary Crossing near Babb, MT is USGS streamgage 05018500 in Montana, monitoring river discharge in hydrologic subbasin 10010002. Discharge records at this site go back to 1918. Typical flow runs near 591.5 cfs in July and 64.2 cfs in April, with the higher of the two arriving in July. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.
View live conditions & forecast →
Gauge details
- State
- Montana
- Gauge elevation
- 4,455 ft
- Subbasin (HUC-8)
- 10010002
- Coordinates
- 48.94697, -113.37533
- USGS site number
- 05018500
- Records begin
- 1918-07-01 (108 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for St. Mary Canal at St. Mary Crossing near Babb, 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 |
|---|---|---|---|---|
| 580 | 603 | 611 | ||
| 497 | 606 | 615 | ||
| 414 | 582 | 631 | ||
| 424 | 592 | 625 | ||
| 322 | 488 | 627 | ||
| 308 | 467 | 616 | ||
| 311 | 472 | 618 | ||
| 301 | 457 | 609 | ||
| 288 | 434 | 596 | ||
| 286 | 430 | 596 | ||
| 282 | 416 | 588 | ||
| 281 | 411 | 580 | ||
| 283 | 409 | 574 | ||
| 283 | 408 | 573 |
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 108 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
Only 10 of 12 months have enough record to summarize; the rest are omitted.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| February | — | 0 | — | |
| March | 0 | 0 | 215.7 | |
| April | 0 | 64.2 | 550.6 | |
| May | 0 | 494.8 | 658.1 | |
| June | 16.5 | 588.4 | 693 | |
| July | 260.2 | 591.5 | 693.5 | |
| August | 214.2 | 577.2 | 687.5 | |
| September | 0 | 239 | 623.1 | |
| October | 0 | 0 | 107.2 | |
| November | 0 | 0 | 37.6 |
All values in cubic feet per second (cfs).
Common questions
- When does St. Mary Canal at St. Mary Crossing near Babb, MT normally run highest?
- July, on the long-term record. The median daily flow that month is about 591.5 cfs, against 0 cfs in February, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for St. Mary Canal at St. Mary Crossing near Babb, MT?
- It depends on the month. In March, half of days historically fall near 0 cfs, with the middle 80% of days between 0 and 215.7 cfs. The month-by-month table on this page gives the full range.
- How long has St. Mary Canal at St. Mary Crossing near Babb, MT been measured?
- Discharge records at USGS site 05018500 begin in 1918, about 108 years, covering roughly 5,974 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for St. Mary Canal at St. Mary Crossing near Babb, 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 St. Mary Canal at St. Mary Crossing near Babb, MT?
- The gauge sits at 48.94697, -113.37533, in Montana, in hydrologic subbasin 10010002, at an elevation of about 4,455 feet.
- Can I use St. Mary Canal at St. Mary Crossing near Babb, 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.