Western Flows

Tuolumne River At Grand Canyon Of Tuolumne

Above Hetch Hetchy Stream Gauge USGS: 11274790 Provisional Data Last Updated: May 26, 08:22 PM PT

Current Flow

1,270 cfs
Falling

Water Temp

49.6 °F
Safe (< 65°F)

Expected Weather

Temp --°F
Wind -- mph
Rain Chance --%
Pressure -- hPa

Location

Basin: Upper Tuolumne County: Tuolumne Elevation: 3,814 ft Drainage Area: 301.0 mi²

System Insights

  • Water temperature is 50°F — below 50°F, the threshold associated with cold shock risk for immersion.

  • Real-time flow is running well above current model projections. On-the-ground conditions are outpacing the forecast.

Verify access, permits, and local conditions before entering any waterway.

Today's Weather

Forecast Details

Morning

At 6 AM: 54°F and Mainly Clear, wind NW at 12 mph. By 10 AM: 58°F and Mainly Clear, wind W at 10 mph.

Afternoon/Evening

At 2 PM: 51°F and Overcast, wind W at 12 mph. By 6 PM: 50°F and Light Drizzle, wind NW at 11 mph.

Overnight

Dropping from 44°F at 10 PM to 42°F by 4 AM. Conditions Clear with wind SW at 3 mph.

3-Day Outlook

🌔 Waxing Gibbous

Today, May 26

🌧️

60° / 44°

Chance of Rain: 35%
5:40 AM 8:10 PM

Wednesday, May 27

❄️

52° / 42°

Chance of Rain: 39%
5:39 AM 8:11 PM

Thursday, May 28

❄️

54° / 43°

Chance of Rain: 94%
5:39 AM 8:12 PM

Flow Trend & 7-Day Forecast

Source: USGS

The current cfs of 1,270 CFS is running near the historical median of 1,540 CFS for this date, indicating average seasonal water levels.

Current (CFS)
7-Day Forecast
Historical Median

7-Day Water Temperature (°F)

Source: USGS
Current (°F)
Historical Median
68°F Threshold

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Glossary & Methodology

Cubic Feet per Second (CFS)

The standard measure for streamflow. One CFS is equal to one cubic foot of water flowing past a specific point in one second (about 7.48 gallons).

Acre-Foot (AF)

The volume of water needed to cover one acre of land to a depth of one foot. One acre-foot is exactly 325,851 gallons.

Snow Water Equivalent (SWE)

The amount of water contained within the snowpack. It can be thought of as the depth of water that would theoretically result if you melted the entire snowpack instantaneously.

Data Sources

Live metrics and historical medians are aggregated directly from the US Geological Survey (USGS), California Data Exchange Center (CDEC), and National Resources Conservation Service (NRCS). Daily flow statistics represent provisional records and are subject to agency revision.