Western Flows

Middle Fork San Joaquin River

Near Mammoth Lakes USGS: 11224000 Provisional Data Last Updated: May 24, 09:56 PM PT

Current Flow

321.0 cfs
Rising

Water Temp

45.3 °F
Safe (< 65°F)

Expected Weather

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

Location

Basin: Upper San Joaquin County: Madera Elevation: 7,570 ft Drainage Area: 43.8 mi²

System Insights

  • Water temperature is 45°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: 41°F and Clear, wind N at 4 mph. By 10 AM: 57°F and Clear, wind NE at 6 mph.

Afternoon/Evening

At 2 PM: 62°F and Clear, wind SW at 13 mph. By 6 PM: 58°F and Overcast, wind SW at 12 mph.

Overnight

Dropping from 48°F at 10 PM to 43°F by 4 AM. Conditions Clear with wind SW at 3 mph.

3-Day Outlook

🌓 First Quarter

Today, May 24

☁️

62° / 41°

Chance of Rain: 23%
5:40 AM 8:06 PM

Monday, May 25

☁️

60° / 42°

Chance of Rain: 6%
5:39 AM 8:07 PM

Tuesday, May 26

☁️

42° / 29°

Chance of Rain: 15%
5:39 AM 8:07 PM

Flow Trend & 7-Day Forecast

Source: USGS

The current cfs of 321 CFS is running near the historical median of 265 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.