Horseshoe Lake CO2 Area

Horseshoe Lake CO2

U.S.G.S scientists detected naturally occurring Carbon Dioxide (CO2) gas in the vicinity of Horeseshoe Lake and other areas on the Mountain in 1994.  Since then they have been monitoring the gas, measuring the concentration and rate of gas discharged from the ground.  The higher than normal concentrations of CO2 are responsible for killing approximately 120 acres of trees next to Horseshoe Lake and elsewhere on Mammoth Mountain. 

Scientists believe that the CO2 is being released from a gas reservior that has existed for a long period of time deep under Mammoth Mountain.  It is believed that earthquake and magmatic activity beneath the area in 1989 opened channels for the gas to reach the surface. 

CO2 is heavier than air and can collect at high concentrations in depressions and enclosures, posing a potential danger to people, especially small children and pets. 

At a Glance

Permit Info:  Wilderness permit for Red Cones Trail is required for overnight trips.
Usage: Light
Closest Towns: Mammoth Lakes, CA
Water: Potable Water
Restroom: Flush Toilet (2)
Operated By: Forest Service
Information Center: For area information call the Mammoth Lakes Welcome Center (760) 924-5500

General Information


From the town of Mammoth Lakes, continue westward on hwy 203 as it turns into Lake Mary Road and heads into the Mammoth Lakes basin. Lake Mary road dead ends at Horseshoe Lake.


Recreation Areas

Recreation Activities


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