(01-22) 18:34 PST Reno, Nev. (AP) --

A string of storms has brought something Sierra Nevada ski resorts haven't seen much this season: snow.

Lake Tahoe resorts, which have been relying on snow-making machines to stay open, reported the storms have dropped 1 to 2 feet of snow since Thursday. Another storm was expected to dump from 15 to 30 inches overnight at higher elevations around the Tahoe basin by Monday afternoon, according to the National Weather Service.

"It's great to have Mother Nature lending a hand," said Andy Chapman of the North Lake Tahoe Resort Association.

Despite the new snow, Sierra ski resorts still offered limited operations. The Tahoe basin snowpack was only 25 percent of normal for the date.

Around Tahoe, eight of 170 runs were open at Squaw Valley, five of 100 trails were open at Alpine Meadows and 32 of 97 trails were open at Heavenly. Farther to the south, Mammoth Mountain reported 51 of 150 runs open, while Kirkwood said six of 72 trails were open.

Jon Slaughter, spokesman for the Boreal resort atop Donner Summit, said he hoped Monday's storm would allow more terrain to open. Boreal reported 12 of 41 runs open on Sunday.

"I'm thrilled to see we actually have some natural snowfall," Slaughter said. "We're going to be able to rapidly expand the terrain. We should be able to groom more runs."

The storms came less than a week after a group of Paiute, Shoshone and Washoe tribal members performed a traditional ceremony seeking spiritual help to bring snow to the Sierra. Some 200 people took part on Jan. 15 at Homewood on Tahoe's west shore.

The current skiing and snowboarding season stands in marked contrast with last season, when roughly twice as much snow as normal fell in the Sierra and resorts stayed open later than usual to take advantage.