A late-season snowstorm slammed into the Northern California mountains early Monday morning, which dropped between 8-12 inches of snow in various regions in the Sierra Nevada and shut down a major interstate highway near the California/Oregon border.

Interstate 5 northbound was closed by Caltrans District 2 Monday evening between North Yreka and the Oregon border due to heavy snow and treacherous winter driving conditions. Chain controls were up and running over both Interstate 80 and U.S. Route 50 going over the Sierra, as heavy snow pounded the mountains.
While most of the action occurred over the mountains, light rain fell in the early morning hours around Chico, with convective showers popping up around midday. Thunderstorms began to pop up north and east of Chico, moving south. High winds, hail and moderate-to-frequent lightning were the main threats.

Further north, a “bomb cyclone” crashed into parts of the Pacific Northwest, with the most severe impacts seen in the Portland metro area. In 82 years of record keeping, Portland International Airport had its first measurable snow in April. Between three to 6 inches of snow fell in parts of the city, while nearly a foot fell in Washougal, Washington. Tillamook, Oregon, just 6 miles from the beach, measured 1 inch of snow. 

However, it wreaked havoc on the roads and infrastructure, as the heavy, wet snow downed power lines, snow-laden trees and caused headaches for many Monday morning commuters. U.S. Route 26 by the Oregon Zoo was closed as fallen trees damaged an Oregon Department of Transportation truck, while multiple, major thoroughfares leading into the city were also closed due to spin-outs and tree damage. 

The Portland Bureau of Transportation said several major roadways on the westside of Portland will remain closed for days, with no hard date set for reopening. Portland General Electric also states that power will be out for multiple days as they fix power lines downed by the heavy snowfall and fallen trees. 

More storms are forecast to impact both regions, as the jet stream dips southward, a pattern typically seen during the winter months. For Northern California, a second storm is forecast on Thursday, with more significant impacts possible in the mountains due to heavy snowfall. 

A third storm is then forecast to impact the region on Saturday. Valley rain totals will be lighter as the storm will be showery in nature, while the mountains can expect at least a foot of snow by Sunday.

Michael Steinberg can be reached at [email protected] or @MichaelWX18 on Twitter.