Storm roars into Sierra: 180 mph winds, whiteout blizzard conditions, avalanche warning

TRUCKEE -- A potent, warm Cat. 4 atmospheric river crashed into the Sierra Tuesday, whipping up hurricane-force wind gusts, triggering whiteout blizzard conditions, and prompting an avalanche warning for the Lake Tahoe area.

According to the researchers at the University of California's Sierra Snow Lab, temperatures were too warm at the higher elevations to produce snow on the overnight hours.

"Windy with a mix of rain and snow this morning, primarily rain," the lab posted on Twitter. "We had 2.8" of new soggy wet slush at the 8 a.m. measurement this morning. We're expecting a transition to snow sometime over the next several hours."

Even as they posted their observation, conditions were already starting to change as hurricane-force winds began ripping through the ski runs at Palisades Tahoe.

Gusts up to 188 mph raked across the slopes beginning at sunrise.

"Sierra ridgetop winds have recorded gusts of 100-120 mph so far this morning," weather service forecasters in Reno said. "Snow levels will lower through the morning with the colder phase of the storm moving in. Snow levels will drop to near 7000' by mid-morning and near lake level by late this afternoon before dipping to around 5000' this evening."

But don't expect the snowfall to be of the light, fluffy variety. Tuesday's storm will be dumping the Sierra cement variety.

"Elevations above 7000  feet could see 12-18" of heavy/wet Sierra cement and up to 2 feet mainly along the Sierra crest," forecasters said.

The heavy wet snow and high winds have forced officials to issue an avalanche warning for Tahoe.

"Very dangerous avalanche conditions," forecasters warned. "Travel in, near, or below avalanche terrain is not recommended and should be avoided. Any steep slopes could be dangerous."