LOS ANGELES (AP) - Thunderstorms embedded with lightning and hail moved across Southern California on Wednesday as winter-like weather persisted through late spring in many parts of the state.

The unusual conditions caused by low-pressure systems dropping out of Canada were expected to continue into the Memorial Day weekend, potentially impacting traditional outdoor activities.

A winter weather advisory was in effect east of Los Angeles in the mountains of San Bernardino and Riverside counties, where recreational areas are normally gearing up for summer by this time of year.

There could be up to 4 inches (10 centimeters) of snow at elevations from 5,500 to 7,500 feet (1,676 to 2,286 meters) and up to 8 inches (20.3 centimeters) at higher elevations, the National Weather Service said.

Caltrans urged motorists to bring chains and warm clothes if they headed up into the mountains.

To the north, the Sierra Nevada was finally free of winter weather advisories after a hefty boost to an already heavy snowpack.

The Squaw Valley resort at Lake Tahoe reported Wednesday morning it had received 32 inches (81.2 centimeters) of snow over seven days, boosting its season total to 714 inches (1,813.5 centimeters).

Southeast of Yosemite National Park, snow showers added to a similar total atop Mammoth Mountain. Winds initially limited operations, but they died down enough to allow more lifts to serve skiers seeking fresh powder.

"May just won't stop delivering snow," the resort said on its website. Mammoth had already had so much snow by February it announced plans to stay open to skiing and boarding through the Fourth of July.

The coast and offshore waters also resembled winter. High surf and small craft advisories were posted along the state's shoreline, with gale warnings for the waters farther out.

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