A dangerous weather event is looming over the Pacific Northwest, raising concerns of potential catastrophic outcomes. Meteorologists from AccuWeather are warning of an imminent threat as a series of intense Pacific storms sweep through the northwestern United States and southwestern Canada. The upcoming storm, expected to be the most powerful of the series, will bring an atmospheric river to parts of Washington and Oregon, posing significant dangers and potential damages.
Throughout this week, the region has experienced rainfall ranging from 0.50 to 2 inches in lower elevations of western Washington and Oregon. Another storm is forecasted to hit from Friday to Friday night, focusing on British Columbia and western Washington, with similar rainfall amounts. The heavy rain could lead to hazardous road conditions, particularly in mountain passes, where a mix of rain and snow may cause slippery surfaces and reduced visibility due to fog and wind.
An even larger storm is anticipated over the weekend, featuring a prolonged plume of intense moisture known as an atmospheric river. This atmospheric phenomenon is expected to unleash a deluge of rain, reaching even the higher elevations of the Olympics and west-facing slopes of the Cascades. The Center For Western Weather and Water Extremes at Scripps Institution of Oceanography has projected a moderate to strong atmospheric river with a rating of 3-4 on their scale, indicating the potential for significant impact.
The upcoming storm is predicted to be one of the most substantial of the winter season, likely surpassing historical average precipitation levels in many areas. Rainfall estimates from the weekend storm alone range from 1-4 inches along the Interstate 5 corridor to 6-12 inches along the mountain ranges of Washington and Oregon. There is a possibility of up to 14 inches of rainfall in certain localized areas.
Residents in the affected regions should be prepared for heavy rainfall and potential flooding, especially in areas near small streams and rivers. With the thawing of snow at higher elevations and the anticipated heavy rain, the risk of avalanches and mudslides also increases. Stay informed and take necessary precautions to ensure safety during this severe weather event.
The likelihood of mudslides and other debris flows is expected to rise in the hilly terrain, particularly affecting the frequently used passes that remain open during the winter months. As the largest storm of the series moves inland, subsequent rounds of moisture from slightly weaker storms will bring with them a decrease in snow levels. By Monday in the mountains of southern British Columbia, and by Monday night and Tuesday in the Cascades of Washington further south, the air temperatures will drop sufficiently for snow to fall and accumulate over the passes, including Snoqualmie Pass in Washington along I-90. Despite the storm from Monday to Tuesday potentially bringing heavy rain to lower elevations, the greatest impact is anticipated to be from northwestern Washington to southwestern British Columbia, where roadways could see ponding leading to slower commutes in cities like Seattle and Vancouver. The storms will also usher in periods of strong gusty winds along the coast, with the potential to topple trees and cause isolated power outages in western Washington and Oregon. The coastal waters are expected to be turbulent during this time, as is typical in the winter season, with rough conditions persisting into Tuesday. For those seeking an enhanced level of safety and an ad-free experience, consider subscribing to Premium+ on the AccuWeather app to access advanced, hyperlocal severe weather alerts. These AccuWeather Alerts™ are generated by our team of expert meteorologists who work around the clock to monitor and assess hazardous weather conditions, ensuring the safety of you and your loved ones.
