Snow falls at Mammoth Mountain on May 16. (Mammoth Mountain via Twitter)

In California’s Sierra Nevada, eight to 15 inches of powder have blanketed the soaring peaks since Wednesday, and more is on the way this weekend. Ski resorts are ecstatic by the late-season snowfall, which will extend the season until July in some areas.

“6 more inches in the last 24 hours. It’s legit good up here,” tweeted Heavenly Ski Resort.

The first in atmospheric rivers — narrow plumes of precipitation off the Pacific Ocean — bombarded California on Wednesday and Thursday with unusually heavy precipitation for the time of year.

“The unincorporated Sonoma County community of Venado recorded 5.19 inches of rain as of early Thursday afternoon, setting a new rainfall record for any day in May,” reported the Mercury News.

The Sacramento Bee wrote that downtown Sacramento nearly doubled its May 16 rainfall record Thursday, registering 0.63 inches compared with the 0.38 inches in 1996.

As that moisture was lifted up the mountain slopes and met the cold air at high elevations, it converted into ankle-deep snowfall.

Mammoth Mountain reported 13 to 15 inches of snow, Squaw Valley 11 inches, and Heavenly eight inches. These ski areas have accumulated between 500 and 700 inches of snow this season. At Squaw, which hit 700 inches on Thursday and intends to stay open until July 4, it is the third-snowiest season on record.

Mammoth’s ski report on Friday boasted it’s “feeling and looking like mid-winter.” The resort, which has received 695 inches this season, plans to keep slopes open until at least July.

These areas are forecast to get pasted by snow again this weekend as the next atmospheric river makes landfall. A winter storm watch is in effect for elevation above 6,000 feet for Saturday afternoon through Sunday night for another eight to 15 inches, and localized amounts to two feet.

Forecast snowfall through Monday morning. (National Weather Service)

A third atmospheric river could spray these areas with additional snow Tuesday and Wednesday.

This cold, snowy pattern is the result of an unusually strong jet stream diving south over the western United States, drawing in cold air from the north and cycling in storms from the Pacific.

Below, see some of the snowy scenes . ..

Groomers work to get the Heavenly Ski Resort ready for a late-season powder day Thursday in South Lake Tahoe, Calif. (Heavenly Ski Resort/AP)