SOUTH LAKE TAHOE, Calif. — After a primer storm exits Lake Tahoe Friday the main event is making its way to the basin.

Officials are advising against traveling in the mountains this weekend with a major winter storm bringing feet of snow, strong winds and whiteout conditions to the Sierra.

Chain controls are in effect Friday morning for the quick hitting storm that dumped 6 inches at Sierra-at-Tahoe and Alpine Meadows. The only section of road where restrictions are not in place is on U.S. Highway 50 from the roundabout in Meyers throughout South Lake Tahoe until chain controls go into effect over Spooner Summit. For more information on road conditions, visit nvroads.com or call 511.

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The National Weather Service issued a winter storm warning for the greater Lake Tahoe area that goes into effect at 4 a.m. Saturday and lasts through 4 a.m. Monday for heavy snow.

Snow accumulation of 20-30 inches are expected for Lake Tahoe with 2 to 4 feet above 7,000 feet and possibly more along the Sierra crest. 

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Strong winds up to 50 mph, and in triple digits on Sierra ridges, combined with heavy snowfall will likely bring whiteout conditions on mountain highways.

“A classic Sierra winter storm will bring significant impacts to the mountains this weekend,” the service said. “Travel across the Sierra is not recommended this weekend and may be impossible at times. If you choose to do so, make sure to have proper supplies and plan for long delays. Strong winds could cause damage to trees and lead to power outages.”

A strong area of low pressure dropping out of the Gulf of Alaska will entertain subtropical moisture along an ideal southwesterly polar jet stream and lead to snowfall rates of 1-2 inches per hour for 18-24 hours, and possibly 2-3 inches per hour from late morning Saturday into the evening, the service said.

The storm will start with snow levels in the 5,000-6,000 feet range with wet heavy snow to fall initially. More fluffy snow will come with the colder part of the storm that moves into the region Saturday night into Sunday with snow levels dropping to western Nevada valleys with 2-plus inches of snow possible for Reno and Carson City and 4 inches in the surrounding areas.

By Sunday, the service said the main cold front will already have moved through the region with cold air, lighter winds, and lingering snow showers in place. 

“Snow accumulations will quickly taper during the day on Sunday, but travel over Sierra passes could remain quite challenging,” the service said.

The Tahoe snowpack is well over average and the incoming storm will only add to it and help ski resorts unlock more terrain.

As of Friday morning, Palisades Tahoe was at 143% of average, Mt. Rose Ski Tahoe was at 166% and Carson Pass was at 157% according to SNOTEL data from the Natural Resources Conservation Service.

The Sierra Avalanche Center has issued a backcountry warning for a period of high avalanche danger from Saturday morning through Sunday morning.

“A winter storm with gale force winds, high intensity snowfall, and feet of new snow accumulation may result in widespread avalanche activity in the mountains,” the advisory said. “Large avalanches could occur in a variety of areas. Travel in and near avalanche terrain is not recommended.”

After the storm moves out, temperatures will be 10-plus degrees below seasonal averages with highs barely over freezing and dropping to single digits overnight with some valleys dropping “easily” below zero, the service said.

The service said the storm door will remain open with activity possible by the middle of next week. Another trough is expected to deepen along the west coast but how much moisture moves into the region remains uncertain as model simulations are yet to align.