SEATTLE (AP) — Black ice and snow covered most roadways as a cold winter storm held the Pacific Northwest in its grips.

Many schools and colleges were closed or opening late on Thursday morning while collisions blocked roads throughout the region.

The National Weather Service reported 1 to 4 inches of snow in the Portland area and another half inch was expected during the day.

Cold temperatures left a layer of ice on roads and sidewalks.

KOMO-TV reports that the National Weather Service Seattle says there was one inch of snow at Sea-Tac Airport at 10 p.m. Wednesday.

NWS Seattle said this is only the 5th time in the past 25 years that there has been an inch or more snow in Seattle after Feb. 15.