Henrys Fork At St Anthony Flow Report
As of July 21, 2026, Henrys Fork At St Anthony is flowing at 1,330 cfs with a gage height of 3.58 ft, rising 7% over the past 24 hours. Source: USGS gauge #13050500, refreshed throughout the day.
Historical Data
Henrys Fork At St Anthony at a glance
How Henrys Fork At St Anthony is running right now, where it sits on the map, and the key gauge stats.
Henrys Fork At St Anthony is flowing at 1,330 cfs, with the water sitting 3.58 ft at the gage. Flow is up 7% since yesterday — a rising hydrograph.
This is USGS gauge #13050500 in Idaho. Over the past 10 days the average has been 1,139 cfs, peaking at 1,330 cfs.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the Idaho flow report.
Engineering Data
Flow-duration statistics and observed peak-flow context computed from this gauge’s complete daily record (USGS #13050500).
Estimate flows at an ungauged site
Drainage-area ratio transfer from this gauge . Most reliable for hydrologically similar sites in the same watershed with area ratios between roughly 0.5 and 1.5.
Percentiles are flow-duration values computed from this gauge’s observed daily record as archived by Snoflo. Return periods are Weibull plotting-position estimates from observed annual maxima, provided as general reference context only. Always verify against official USGS NWIS records. Part of Snoflo for Engineering.
Streamflow Forecast
Over the next 5 days, Henrys Fork At St Anthony Id is expected to hold near today's 1330 cfs, toward roughly 1235 cfs by 2026-07-25 (likely range 1006-1516 cfs) -- about normal for the date.
Powered by PULSE — Snoflo’s forecast engine, trained on this gauge’s full record of storms, snowmelt, and dry spells.
| Date | Expected (p50) | Likely range (p25–p75) | vs normal | Projected stage |
|---|
How does this compare to past years?
Year-over-year overlay, annual peak discharge, the full distribution of daily flows on record, and the gauge's rating curve.
Weather Forecast
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day forecast
Daily temperatures, snow, and rain projected over the next two weeks.
Henrys Fork At St Anthony
Anthony, ID stream gauge measures the flow rate of the Henrys Fork, a major tributary of the Snake River. Its flow is primarily fed by snowmelt, and water is also added by various tributaries along the way. There are several dams along the river, including the Ashton Dam and Island Park Dam. Seasonal trends show that flow rates are highest in the late spring and early summer months due to snowmelt, and lowest in the fall and winter months. The Henrys Fork is known for its excellent trout fishing, and its waters have been immortalized in the writings of famous American author Ernest Hemingway.
Nearby streamflow levels
Cross-check Henrys Fork At St Anthony's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| Henrys Fork At St Anthony Id | 1,330 cfs |
| Teton River Nr St Anthony Id | 695 cfs |
| Falls River Nr Chester Id | 344 cfs |
| Nf Teton River Nr Sugar City Id | 6 cfs |
| South Fork Teton River Nr Rexburg Id | 96 cfs |
| Henrys Fork Nr Ashton Id | 2,070 cfs |
Nearby snowpack data
Snowpack at SNOTEL stations near Henrys Fork At St Anthony. Spring snowmelt is the dominant driver of streamflow in mountain basins -- a deep snowpack upstream means more runoff later in the season.
| SNOTEL station | Snowpack |
|---|---|
| Nohrsc Sugar City 1.9 S | 0 in |
| Menan 4 Nne | 0 in |
| Nohrsc Rigby 1.8 Ne | 0 in |
| Idaho Falls 11.7 Ne | 0 in |
| Driggs 3.4 Nne | 0 in |
| Island Park | — |
River levels & flood safety
- Read the level before you go
- A river that's runnable at one flow can be deadly at another. Check current discharge and gage height — like the values shown above — against the flood-stage thresholds, and remember levels can spike fast after rain or a dam release.
- Respect cold water
- Snowmelt rivers run cold even in summer. Sudden immersion triggers cold-water shock and saps strength within minutes. Wear a PFD, dress for the water temperature (not the air), and never wade or paddle alone.
- Watch for swiftwater hazards
- Strainers (downed trees), undercut rocks, and low-head dams are the deadliest features on moving water. High, fast, muddy water hides them. If in doubt, scout from shore and portage.
- Mind flash floods & releases
- Narrow canyons can flood from a storm miles upstream, and dam-controlled reaches can rise without warning. Know the forecast, the release schedule, and your exit before you launch.
Track Henrys Fork At St Anthony in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when Henrys Fork At St Anthony crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About Henrys Fork At St Anthony
Where does the streamflow data for Henrys Fork At St Anthony come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 13050500. Snoflo refreshes the time series throughout the day. Forecasts come from the NOAA / yr.no feed Snoflo's iOS app uses.
How often is the report updated?
USGS gauges report continuously (typically every 15 minutes). Snoflo pulls fresh values throughout the day — look for the "as of" timestamp on the streamflow hero card.
What's the difference between discharge and gage height?
Discharge (cubic feet per second, or cfs) is the volume of water flowing past the gauge each second. Gage height is how high the water sits at the gauge (feet). They're related by a rating curve specific to each gauge — higher water means more flow, but the exact ratio depends on channel shape.
How is "percent of median" calculated?
Today's discharge is compared to the historical median discharge on this calendar day across the gauge's full record. 100% = right on median; 200% = a very high year; 30% = a drought-level low.
What are flood stages, and is this river safe right now?
Flood stages are NWS-defined gage-height thresholds — Action, Minor, Moderate, Major — marking when nearby roads or floodplains start to be affected. "Safe" depends on your activity and skill: a level that's a fun paddle for an expert can be lethal for a wader. Always check the current level against the thresholds above and the safety links, and when in doubt, stay off the water.
Can I get alerts when Henrys Fork At St Anthony rises?
Yes — flow alerts are managed in the Snoflo iOS app. Favorite this gauge, set a streamflow threshold (e.g. "alert me when discharge crosses 5,000 cfs"), and you'll get a push the moment USGS reports the crossing.
Access the free Henrys Fork At St Anthony report
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