SEATTLE >> A snowstorm that blanketed Seattle and western Washington state into Monday morning prompted widespread school closures, flight cancellations and power outages for more than 100,000 electrical utility customers, officials said.

The storm that started Sunday night caused a messy morning commute for Seattle residents, and a winter storm warning remained in effect Monday for the greater Seattle area.

Forecasters said as much as 30 inches of snow could fall in the Cascade Mountains, and Interstate 90 over Snoqualmie pass was closed to motorists Monday morning because of heavy snow before reopening in the afternoon.

The storm hit Seattle after one storm after another has slammed Portland, Oregon. Forecasts for a major snowstorm for Portland turned out false as temperatures remained above freezing. But heavy rain fell in Portland and pushed rivers toward flood stage.

In northwestern Montana, a strong winter storm halted highway and rail traffic over Marias Pass along the edge of Glacier National Park and led schools to cancel classes on Monday. The National Weather Service issued a winter storm warning for the region until 11 p.m. and a blizzard warning along Flathead Range

At Seattle-Tacoma International Airport dozens of flights were cancelled at Seattle-Tacoma because of snow and ice.

Alaska Airlines spokeswoman Bobbie Egan said the carrier had trouble getting some employees to the airport and that passengers faced delays because workers had to deice jets.

“It’s taking 30-45 minutes to deice a single plane, which is a significant issue to get planes out,” Egan told KOMO. “It’s a messy scene and we apologize for that, but it’s a severe event.”

In Seattle’s hilly Queen Anne neighborhood, children and parents took advantage of the neighborhood slopes to sled and use boogie boards to snowboard. Snow angels and snow creatures were also being made.

“It’s awesome, especially because I had a life-skill test today and now it’s delayed until Thursday,” said Allette Franklin, 12.

Her 11-year-old friend Josie Kinney agreed. “It’s almost a miniature Christmas,” she said.

Nearby, Stephanie Krammel was making a snowman with her daughter.

“This doesn’t happy very often in Seattle, and nobody knows what to do because the roads are normally a mess. A snow day in Seattle . is very rare and very fun, I would say,” she said.