Rockslide shuts down southbound 101 in Marin; Bay Area peaks covered with snow

SAN FRANCISCO -- A weekend storm front moved eastward early Monday, but its impact was still being felt with snow on Bay Area peaks and a rockslide on Highway 101 in Marin that damaged several vehicles.

The California Highway Patrol reported a rockslide about 5 a.m. at Rodeo Ave.  Arriving officers found one vehicle with major damage and others pulled over after having been impacted by debris. 

No injuries were immediately reported, but the slide triggered a SigAlert as southbound traffic was being routed off the freeway at Marin City.

Officials brought in heavy equipment to remove the debris. The highway reopened just before 7 a.m., but the closure left stop-and-go traffic and created delays.

Marin drivers were warned to find other routes into San Francisco during the morning commute.

Meanwhile, the National Weather Service said conditions on the backend of the storm front -- frigid temperatures and isolated downpours -- were a perfect combination to leave a dusting of snow on at Mt. Hamilton in the South Bay and also the highest elevations of the Diablo Range.

"Snow levels are already dropping early this morning to around 3,700 feet in the North Bay and around 4,300  feet at Point Sur," weather forecasters said. "The arriving moisture should coincide  with these lowering levels to produce snowfall in the region's higher peaks."

"So for the Santa Lucias the most likely amounts are around 2-4 inches with 6-8 inches possible in the higher elevations. However a reasonable worst case scenario could produce over 8 inches locally if things line up just right moisture and temperature-wise."  

Elsewhere across the Bay Area, the wintry conditions triggered a freeze warning in the North Bay until 9 a.m. with temperatures dipping into the 20s.

"Late Saturday night into Sunday, cold air moved in and snow levels dropped down to about 3,500 feet," National Weather Service Meteorologist Roger Gass said Monday.

The highest elevations of the Mayacamas Mountains in the North Bay, the Diablo Range in the East Bay and the Santa Lucia Range along the Central Coast all saw anywhere from less than an inch to 3 inches in places, Gass said.

Some areas even experienced snow-related driving hazards, which led the California Highway Patrol to close a stretch of State Highway 29 in Napa County between Calistoga and the Lake County line.  

While the snow in the Bay Area was scenic, the storm's blast created chaos in the Sierra as more than 5 feet of new snow fell over the weekend.

The front also battered the region with hurricane-force gusts. At Palisades Tahoe's Alpine run a gust of 165 mph was recorded on Saturday.

"The snow showers will continue for much of the Sierra through early Monday morning," the weather services Reno office warned.

For much of Saturday, the snow had a high moisture level. Known as 'Sierra cement' the thick, heavy snow triggered the avalanche warning.   

"Several feet of new snow and strong winds will result in dangerous avalanche conditions in the mountains," forecasters said. "Avalanche activity could be widespread, and some avalanches could be large and destructive."

As of Sunday afternoon, 70 inches had fallen at Sierra-at-Tahoe, 59 inches at Palisades Tahoe, 51 inches at Kirkwood and 60 inches at Soda Springs.

The storm's major impact across the Bay Area was flooded roadways that led to numerous accidents and trees toppling.

Crews worked early Monday to clear large tree that fell overnight in Lafayette at Pleasant Hill Road and Pleasant Lane.

There was also cleanup going on in Monte Rio where 50 mph toppled trees and limbs into several homes in rural Sonoma County during the weekend storm.

On Alder Dr. in Monte Rio, a tree slammed into a two-story home. Over on River Blvd., a large redwood branch fell, damaging three vehicles and an Airbnb rental.

"It was like an earthquake," said Cynthia Cook, one of the Airbnb renters who was in town from Pacifica to celebrate a friend's birthday. "A redwood branch came down and hit all three of our cars that aren't operational right now."

A large tree also fell into a house on Old Monte Rio Rd. in Guerneville. The tree brought down power lines, along with the top half of a utility pole, blocking Highway 116 for about 30 minutes.

In San Francisco's Golden Gate Park, a massive redwood fell in Hellman Hollow, forcing organizers to alter Saturday's race course at the National Club Cross County Championships.

"The tree was a Monterey Cyprus, approximately 30 feet tall," a spokesperson for San Francisco Recreation & Parks told KPIX. "It went down around 10:30 a.m. No injuries and we relocated the race to the upper Polo Fields track."