Mammoth Mountain officials said the slide occurred during avalanche mitigation work following a significant Sierra Nevada snowstorm, during which about six feet of snow fell in 36 hours.

Ski patrollers from mountain resorts in California, Nevada, and Colorado are at Mammoth Mountain in the Eastern Sierra, helping to provide safety following an avalanche that caught two patrollers, leaving one critically injured.

Two ski patrollers were caught in an avalanche Friday after heavy snowfall from a recent atmospheric river triggered a slide on Lincoln Mountain in California’s Sierra Nevada.