Rivermatics

USGS Streamgage 13050500

Henrys Fork at St Anthony, ID

Henrys Fork at St Anthony, ID is USGS streamgage 13050500 in Idaho, monitoring river discharge in hydrologic subbasin 17040203. It sits on the Henrys Fork, alongside 4 other gauges Rivermatics tracks on the same river. It drains a watershed of about 1,770 square miles. Discharge records at this site go back to 1919. Typical flow runs near 1,168.7 cfs in July and 2,003 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.

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Gauge details

State
Idaho
Drainage area
1,770 sq mi
Subbasin (HUC-8)
17040203
Coordinates
43.96694, -111.6725
USGS site number
13050500
Records begin
1919-03-01 (107 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Henrys Fork at St Anthony, ID. 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
1,627 1,691 1,760
1,584 1,686 1,792
1,530 1,676 1,820
1,472 1,665 1,844
1,408 1,638 1,845
1,356 1,609 1,841
1,304 1,578 1,826
1,275 1,556 1,825
1,241 1,527 1,809
1,207 1,499 1,797
1,190 1,485 1,804
1,151 1,458 1,796
1,120 1,429 1,778
1,100 1,407 1,764

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 107 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 1,136.5 1,550.3 2,060.3
February 1,166.2 1,572.4 2,034.8
March 1,152.6 1,521.6 2,041.3
April 1,175 2,003 3,187.7
May 1,673.5 3,355.5 5,942.3
June 1,056.8 2,603 4,989.7
July 759.3 1,168.7 2,192.3
August 836.6 1,185.2 1,725.2
September 833.5 1,226 1,736.3
October 815.4 1,254.2 1,896.5
November 1,103 1,461.3 2,126
December 1,130.6 1,535.8 2,066.1

All values in cubic feet per second (cfs).

Common questions

When does Henrys Fork at St Anthony, ID normally run highest?
May, on the long-term record. The median daily flow that month is about 3,355.5 cfs, against 1,168.7 cfs in July, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Henrys Fork at St Anthony, ID?
It depends on the month. In January, half of days historically fall near 1,550.3 cfs, with the middle 80% of days between 1,136.5 and 2,060.3 cfs. The month-by-month table on this page gives the full range.
How long has Henrys Fork at St Anthony, ID been measured?
Discharge records at USGS site 13050500 begin in 1919, about 107 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 Henrys Fork at St Anthony, ID?
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 Henrys Fork at St Anthony, ID?
The gauge sits at 43.96694, -111.6725, in Idaho, in hydrologic subbasin 17040203, draining roughly 1,770 square miles.
Can I use Henrys Fork at St Anthony, ID 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.

Upstream and downstream on the Henrys Fork

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Henrys Fork in full.

Other gauges in this subbasin