SEATTLE - Fierce storms in the Pacific Northwest sent rivers bursting from their banks, spilled boulders and trees into a major highway and spawned a rare tornado that snapped power poles and battered homes. They've also had one positive effect - easing drought concerns after an unusually dry summer.

The big storms that killed at least two people in Oregon this week shifted into California, where snow coated the slopes of the Sierra Nevada. But forecasters said mudslide danger on saturated hills in the Northwest would remain high through the weekend.

A rain-soaked hillside collapsed Wednesday north of Portland, on the main highway connecting Washington and Oregon, stranding thousands of motorists on Interstate 5. Road closures in both states frustrated drivers who were trying to navigate alternate routes that took them hours out of their way.

"It was crazy, and I was scared," said Diane Smith of Lacey, Wash., who was stuck for three hours behind the I-5 landslide and then drove a steep, windy road to get around it.

Two lanes of the interstate were back open by Thursday night, and officials said they hoped to have all three reopened by late Sunday.

More rain is on the way through the weekend.

The moisture is helping to fill reservoirs earlier and recharging the groundwater, said Scott Pattee, water supply specialist with the Natural Resources Conservation Service based in Mount Vernon.

But "a lot of this rain is going down hard so it's flowing straight through the snowpack, and it's not adding to it," he added.

Much of Washington's water supply depends on mountain snowpack that builds over winter, and melts in spring and summer.

The latest report from the U.S. Drought Monitor on Thursday showed the area west of the Cascade Mountains in Washington is no longer in drought.

Cities such as Seattle, Everett, and Tacoma implemented water shortage plans when unseasonably dry summer conditions left the region parched.