RENO, Nev. (AP) — The second of back-to-back winter storms was making its way Friday toward the Sierra Nevada, where up to 2 feet of snow already has fallen on the mountains around Lake Tahoe — much to the delight of area ski resorts.

Mountain highways reopened under sunny skies Friday and classes resumed two hours late at schools around the lake where they were closed on Thursday.

A winter storm warning expired at 4 a.m. Friday but a new one goes into effect at 4 a.m. Saturday into Monday morning for most of the Sierra from south of Yosemite National Park to north of Lake Tahoe and Reno.

“Another potent and prolonged winter storm will approach the area overnight, bringing more mountain snow and valley rain on Saturday as snow levels will be initially higher than the previous storm,” the National Weather Service in Reno said Friday.

The most snow so far, 30 inches (76 cm), was recorded late Thursday and overnight south of Yosemite at the top of Mammoth Mountain ski resort near Mammoth Lakes.

“This round of storms adds to what’s already been the best early season for snowfall in a decade,” said Lauren Burke, a spokeswoman for Mammoth Mountain.

“It’s full on winter up here and with a couple more feet in the forecast for the weekend it’s only going to get better,” she said.

Elsewhere in California, 2 feet (61 cm) of snow was reported at Homewood resort on Tahoe’s west shore, 22 inches (56 cm) at Northstar in Truckee, 20 (51 cm) at Palisades near Tahoe City and 19 (48 cm) at Mount Rose on the southwest edge of Reno.

Another 6 to 17 inches (15-42 cm) is expected into the weekend at elevations above 7,000 feet (2,133 meters), and 4 to 10 inches (10-25 cm) below that around Lake Tahoe, the National Weather Service said Friday.

The weather service said snow levels will drop to lower elevations on Sunday and some snow showers may linger into the first part of next week.

The Sierra Avalanche Center lowered the avalanche danger in the backcountry around Tahoe from high to “considerable” on Friday but warned that large, human-caused avalanches remain likely.

“Even though chances for natural avalanches may have lessened, dangerous and unusual avalanche conditions still exist,” the center said Friday. “Triggering avalanches would be easy on steep slopes in exposed and sheltered areas where new snow rests on top of weak snow or where wind-drifted snow exists near ridges. ”