SAN FRANCISCO (CBS SF) — The slow migration of holiday weekend skiers from the San Francisco Bay Area to the Sierra resorts was well underway Friday as the first of two storm fronts dumped more than a foot of new snow at the higher elevations around Lake Tahoe.

As skies cleared Friday afternoon, chain requirements were lifted on I-80, according to the California Highway Patrol.

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“The first of several storms will exit this morning with improving conditions,” the weather service said “Much of the precipitation will be out of the region by daybreak, or shortly after, as the system moves quickly to the southeast…The next system will move into the region tonight and Saturday, starting across northeast CA/northwest NV by late this evening, the northern Sierra and much of northern NV overnight and finally the rest of the Sierra/western NV during the day Saturday. This storm is a little colder than the one exiting this morning. So expect several inches of accumulating snow.”

Mammoth Mountain south of Yosemite National Park reported 18 inches of snow by early Friday with 16 inches at Alpine Meadows on Tahoe’s west shore.

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A foot was recorded at North Star, 11 inches at South Lake Tahoe and about a half-foot on the north shore at Incline Village and Mount Rose near Reno.

“Mother Nature lined this one up perfectly!” the resort said in its weather report.

Bluebird conditions were expected to be followed by a second storm late Friday into Saturday and then another storm late Sunday into Monday, “arguably the worst time during the holiday weekend,” the National Weather Service’s Reno office wrote.

“This third storm in the series will usher in more gusty winds, chances for snow and impacts to the end of the holiday weekend,” the weather service said. “Forecaster confidence remains high for travel disruptions along the Sierra passes with all of these systems and some concerns for western Nevada roadways too.”

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Although modest, the storm added to the lagging Sierra snowpack, an important part of California’s water supply. The Feb. 3 snowpack survey found its water content was 70% of average to date.