Big winds, high waves close the I-90 floating bridge as Puget Sound and the surrounding area was buffeted by wild weather Sunday.

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Strong winds and high waves forced closure of the westbound lanes of the Interstate 90 floating bridge across Lake Washington for about four hours Sunday, tangling freeway traffic on the Eastside for more than two miles.

The powerful gusts also broke branches, knocked down trees and power lines and caused mostly minor damage throughout Puget Sound.

“We’re at the mercy of the winds and waves,” said Washington State Department of Transportation spokeswoman Frances Fedoriska, at about 5 p.m. Sunday, while the I-90 span remained closed. “We need one of them to subside below the thresholds.”

Under a new standard recently adopted to prevent structural damage, state officials will close the westbound span when winds from the north measure above 26 mph at the same time waves off Lake Washington are observed higher than two feet.

That happened about 2:18 p.m., Fedoriska said, with at least one wind gust measured at about 30 mph during the closure.

“The strong winds combined with wave heights and vehicle weights can cause unnecessary wear and tear on the pontoons,” Fedoriska said.

The new standard was established based on a recent Sound Transit analysis that showed the bridge’s pontoons are susceptible to damage during strong wind events, according to a WSDOT blog posting.

As the winds died down, tranportation officials re-opened the bridge by 6:30 p.m.

Wind-whipped whitecaps on Lake Washington underscored a cold and wild weather day in Western Washington on Sunday.

Snow flurries and strong winds blew into the region, with temperatures dipping to the low 20s.

“Some places got snow; Stanwood got 10 inches,” National Weather Service meteorologist Johnny Burg said Sunday. “But in Seattle, we really didn’t see anything that stuck.”

The strongest gusts were felt up north, with south Lopez Island measuring gusts of 62 mph by Sunday evening. Seattle felt wind gusts between 30 and 40 mph, downing trees and causing more than 40 power outages and several small brush fires across the city.

High winds took down a tree that downed a power line in West Seattle about 3:30 p.m., temporarily killing power to about 4,100 customers in Burien, according to Seattle City Light.

Winds in the Seattle area were expected to die down by midnight, but temperatures in the mid-20s and low-30s are expected to hang around through next week, with a chance of snow Wednesday and Thursday, Burg said.

“For tonight and for the next couple days, it’s going to be cold and there could be slick spots out there,” Burg added. “So, people should be careful.”