Rivermatics

USGS Streamgage 12370000

Swan River near Bigfork, MT

Swan River near Bigfork, MT is USGS streamgage 12370000 in Montana, monitoring river discharge in hydrologic subbasin 17010211. It drains a watershed of about 672 square miles. Discharge records at this site go back to 1922. Typical flow runs near 1,535.7 cfs in July and 1,352.1 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.

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Gauge details

State
Montana
Drainage area
672 sq mi
Gauge elevation
3,078 ft
Subbasin (HUC-8)
17010211
Coordinates
48.02423, -113.97882
USGS site number
12370000
Records begin
1922-05-01 (104 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Swan River near Bigfork, 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.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
591 637 694
591 658 764
567 633 739
557 626 739
551 626 748
536 605 717
522 587 691
506 567 660
487 545 630
473 530 610
463 518 595
453 509 585
445 501 576
435 491 564

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 103 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 333.4 448.4 695.5
February 317.9 434.4 753
March 354.4 572.2 1,037.6
April 726.4 1,352.1 2,528
May 1,622.9 2,582.6 4,395.2
June 1,895.3 3,071 4,996
July 818.3 1,535.7 2,555.2
August 421.9 653.2 996
September 351 487.6 732.4
October 339.3 494.8 770.9
November 366.8 542.6 870.4
December 354.8 484.9 823.8

All values in cubic feet per second (cfs).

Common questions

When does Swan River near Bigfork, MT normally run highest?
June, on the long-term record. The median daily flow that month is about 3,071 cfs, against 434.4 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 Swan River near Bigfork, MT?
It depends on the month. In January, half of days historically fall near 448.4 cfs, with the middle 80% of days between 333.4 and 695.5 cfs. The month-by-month table on this page gives the full range.
How long has Swan River near Bigfork, MT been measured?
Discharge records at USGS site 12370000 begin in 1922, about 104 years, covering roughly 9,201 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Swan River near Bigfork, 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 Swan River near Bigfork, MT?
The gauge sits at 48.02423, -113.97882, in Montana, in hydrologic subbasin 17010211, at an elevation of about 3,078 feet, draining roughly 672 square miles.
Can I use Swan River near Bigfork, 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.

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