NORTH BEND, Wash. - Interstate 90 over Snoqualmie Pass will remain closed until 6 p.m. Friday for avalanche control work, DOT officials said early Friday after another avalanche fell overnight.

Washington Department of Transportation Regional Administrator Don Whitehouse said after crews spend the next nine hours on avalanche control, they'll reassess when the interstate will reopen.

Another avalanche about 150 feet wide buried the eastbound lanes about 2 a.m. Friday. A 72-mile stretch of I-90 from milepost 34 in North Bend to milepost 106 in Ellensburg remains closed indefinitely.

No one was injured in the latest avalanche, which was smaller than avalanche that buried the westbound lanes of I-90 Wednesday. The pass was closed for 28 hours starting Tuesday morning because of heavy snow and avalanches. Less than six hours later after it reopened Wednesday, one of the largest avalanches on Snoqualmie hit two cars and the freeway was closed again. The slide caused no injuries but shook up drivers.

Long shutdowns of I-90 over Snoqualmie Pass, the main east-west route across the Cascade Mountains, have increasingly disrupted the state's economy, Gov. Chris Gregoire said. Transportation Secretary Paula Hammond said 7,000 trucks cross the pass each day, about one quarter of total traffic on the pass.

"We want to keep the freight moving, we want to keep people moving, we want to let them get where they want to go, but our most important thing is safety right now, and our experts aren't going to let people up there unless it's safe," said Bogenschutz.

Drivers can take alternate routes at Stevens Pass and White Pass. U.S. 2 over Stevens Pass was closed for seven hours Thursday as crews cleared the wreckage of several tractor-trailer rigs. The other main winter route across the Cascades, White Pass, remained open with traction tires required on cars and chains on trucks.

Truckers, however, will be looking at a long detour through Portland over I-84 and up to I-82 to connect with I-90 on the east side of the Cascades.

Washington State Patrol also says don't think about coming to Snoqualmie Pass to ski or play around in the snow. They'll be checking identifications to make sure either people live there or they are first responders or other essential personnel.

Gregoire declares state of emergency

Gregoire declared a state of emergency Thursday for 15 counties, mostly in snowbound Eastern Washington, which has been nearly cut off from the state's west side by mountain avalanches and paralyzed by inability to get all the snow off streets and highways.

"The snowfall this month has been relentless and this proclamation will help counties with response efforts," Gregoire said in a statement.

More than five feet of snow has fallen this week and the National Weather Service predicted another 4 to 10 inches by 4 p.m.

The governor's announcement, after briefings by municipal and county officials in Spokane, allows local governments and the state Transportation Department to bypass normal bidding requirements so they can quickly hire private companies to help with snow removal. The emergency proclamation includes Spokane, Adams, Clark, Columbia, Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, Skamania, Stevens, Walla Walla, Whitman, Yakima and King counties.

The governor noted that several Western Washington counties adjoining mountain passes are covered under her proclamation but added the emergency was not severe enough to justify an application for federal disaster aid.

Windblown snow closed more roads and schools Thursday in Eastern Washington.

Washington State University in Pullman joined a long list of colleges, universities and school districts in the eastern half of the state that suspended operations and canceled classes because of treacherous driving conditions. Classes were canceled again Friday and the University of Idaho in Moscow, just across the state line, also was closed.

Near Fairchild Air Force Base, outside Spokane, a 20-mile section of U.S. 2 was reopened Thursday afternoon after being closed for about 10 hours by blowing and drifting snow, the Transportation Department said.

A new storm that passed through the region early Thursday dumped as much as 7 inches of new snow on Spokane, with outlying areas reporting as much as a foot. Occasionally heavy snow continued falling overnight but some respite was predicted by midday Friday. In the southeast corner of the state, heavily traveled U.S. 195 was closed for more than six hours Thursday from south of Pullman, home of WSU, to the Idaho border.

Schools in Spokane were closed for a fourth consecutive day Thursday and will not reopen this week because of snowy and icy roads. The snow days in Spokane, which has one of the largest public school systems in the state with 30,000 students, were the first since 1996.