The National Weather Service issued a warning Wednesday about the dangers of so-called “roofalanches” as an atmospheric river barrels down on the snow-covered Sierra Nevada, reports SFGate.
- Related: NOAA: Winter Storm Warning Issued For California | 2-5 FEET of Snow Above 8,000ft Today – Thursday
The likelihood of deadly roofalanches — the sudden release of snow from rooftops — increases when heavy rain pummels roofs already covered in snow, the Reno office of NWS said Wednesday. Meteorologists advise people to avoid standing or playing under roofs throughout the Sierra Nevada.
“With several feet of snow on roofs throughout the Sierra these collapses can seriously injure or even kill someone,” the weather service said. “Use extra caution anywhere snow may shed from roofs.”
Meteorologists said heavy rain is possible below 7,000 feet and predict the rain will likely give way to snowfall by Friday through Sunday as a colder air mass blows into the Sierra.
NWS also issued an avalanche advisory for Wednesday morning through Thursday morning due to heavy snowfall, intense southwest winds, and rainfall at lower elevations, all of which increases the likelihood of deadly wet-slab releases. Avalanche conditions Wednesday were considered “very dangerous” on mountain peaks to below the tree line. Travel in or under avalanche terrain should be avoided, NWS said.
While deadly snowfalls from California rooftops are rare, they are not unheard of. Last year a San Francisco and her seven-year-old son were killed at Kirkwood Mountain Resort in Alpine County when they were buried by snow that slid off the roof of the ski resort.