Winter weather enveloping the Sierra Nevada mountains kept skiers from hitting the slopes on Friday at the start of the Presidents' Day holiday weekend, with snow so deep that plows could not tackle it and cities scrambled to find places to pile it.

Several routes to the ski mecca of Lake Tahoe shut down, including about 70 miles of Interstate 80 from Colfax, California, to the Nevada state line, as snow dumped on the mountains for a fourth straight day.

I-80 was reopened to passenger vehicles Friday evening. Chains were required for travel in many other parts of the towering Sierra Nevada.

"All avid skiers are itching to get out on the mountain, but the roads are pretty treacherous right now," said Kevin Cooper, marketing director for Lake Tahoe TV.

The storm was expected to dump between 3 and 6 feet of fresh snow in a region where some ski resorts reported getting 3 feet since Thursday. Officials warned of avalanches in the greater Lake Tahoe Area, where heavy snow and high winds are expected through Sunday.

Storms also have swamped much of the state with heavy rain that crumbled roads and flooded a resort north of San Francisco where a kayaker paddled through a meeting room after a nearby river swelled over its banks. The onslaught extended into Arizona and other parts of the west coast, with a winter blast also hitting Missouri.

In California, the heavy snow forced some skiers to cancel their plans.

Aura Campa of Oakland and her partner were hoping to take advantage of their season passes and the fresh powder at Squaw Valley-Alpine Meadows resort, but a near-accident on an icy road last weekend made them reconsider.

When a main highway through the Lake Tahoe area was crushed with traffic, she drove her SUV on a side road. Her vehicle didn't have chains, and when it was going uphill, the vehicle went into reverse.