Reservoir Report

Mammoth Pool reservoir

California, USA USBR
Today high
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Tonight low
--
Current storage
103,364acre-ft
% of normal
-12%
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Right now · current storage
Mammoth Pool
USBR · MPL
103,364 acre-ft
As of 2026-05-11
Seasonal avg
118,089
Record max
128,184
24h change
-0.8%
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Mammoth Pool -- None reservoir
Mammoth Pool None
About this reservoir

Mammoth Pool

Mammoth Pool is a reservoir located in the Sierra National Forest of California. The history of the reservoir dates back to the early 1900s, when it was constructed as part of the San Joaquin Electric Company's hydroelectric system. The reservoir is fed by several creeks and streams, including the San Joaquin River, as well as snowpack melt from the surrounding mountains. The hydrology of the area is complex and includes a network of aqueducts and pipelines that deliver water to agricultural and urban areas in the Central Valley. The surface flow from Mammoth Pool is used for irrigation in the Fresno area, while the snowpack provides important water resources for the state. The reservoir is also a popular recreational destination, with opportunities for fishing, boating, and camping.

StateNone
OperatorUSBR
Site IDMPL
Percent of normal-12%
Last updated2026-05-11
Records since2021
Storage trends

Daily levels at Mammoth Pool

Storage volume, pool elevation, and total release plotted from the operating agency's daily observations.

Storage

acre-ft · code 2

Detailed forecast

Plan around the weather

Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

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Deep dive

5-day forecast table

Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
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Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

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Track Mammoth Pool in the Snoflo app

Save this reservoir as a favorite and set push alerts when storage crosses a threshold (e.g. "alert me at 80% of normal").

FAQ

About Mammoth Pool

Where does the data for Mammoth Pool come from?

Daily storage, pool elevation, and release rates are sourced from USGS, USBR, and USACE monitoring stations. Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.

How often is the report updated?

Storage observations are updated daily by the operating agency. The 15-day weather forecast refreshes throughout the day. Snoflo caches and renders the most recent observation -- check the "as of" timestamp on the storage card.

What does the Hazard hazard rating mean?

The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.

What's "% of normal"?

The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).

Can I get alerts when storage crosses a threshold?

Yes -- alerts are managed in the Snoflo iOS app. Favorite this reservoir, set a threshold, and you'll get a push the moment conditions cross.

Premium feature

Favorites and alerts are part of Snoflo Premium. Save reservoirs, set storage thresholds, and get push notifications when conditions cross.

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Manage alerts in the Snoflo app

Custom alerts are configured in the iOS app -- favorite this reservoir, set a threshold, and you'll get a push the moment conditions cross.

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