SEATTLE -- As the clouds parted at noon over downtown Seattle Thursday, the sun finally popped out. KIRO 7 reporter Chris Legeros found as temperatures climbed, so did the spirits of those on the streets.

"Everybody's in a great mood, I've yet to see one person today in a bad mood," said Ed Schweihs in Seattle.

Less than a month ago, snow was still falling in areas around the Puget Sound with rains and even hail. Now record high temperatures are slated for the days ahead.

As Kenny Kramer at the Northwest Weather and Avalanche Center predicted, the snow would separate from the slopes as temperatures rise, sparking an avalanche.

Highway 20 in the North Cascades is closed because of avalanche danger. The highway will remain closed all weekend, the Washington State Department of Transportation said.

The agency said one slide came across the highway at Liberty Bell Mountain, Mile Post 165, forcing WSDOT to close gates at Mile Post 134 on the west side and at 170.6 on the east side.

Crews were able to move the snow out of the way to make sure travelers could get through the passes.

Officials still warn more avalanches and flooding could occur with temperatures continuing to rise and reach the upper 80s and low 90s on Friday and Saturday.

Kramer said backcountry hikers and skiers should be "incredibly careful."

In addition, rivers are expected to rapidly rise. Larry Schick from the Army Corps of Engineers said water volumes could double or triple.

"Our emergency management people are watching Eastern Washington, where some of these rivers may flood or cause some problems," said Schick.

The Stehekin, Methow, Naches and Yakima rivers could reach flood stage. No is flooding expected in Western Washington, but swift, icy waters of local rivers could be dangerous if people try to float or wade in them to keep cool.

"We just want to caution people that it will be very dangerous to be out on or near the water," said Schick.

The King County Health Department issued a warning that warm spring weather often brings a spike in drownings.

Officials said swimmers should know that rivers full of snow melt can quickly cause hypothermia that can weaken even the strongest swimmer. They urged people to wear a life jacket and keep children within reach near any type of water.