Pineapple express sets sights on Oregon into Friday night
The latest storm in the pineapple express will focus on Oregon into Friday evening. Some streams and rivers will quickly surge to major flood levels, posing risks to lives and property.
Extreme weather stretched across a huge swath of the West from Washington all the way to Colorado on Dec. 16-17.
Another dose of the Pineapple Express will affect the Pacific Northwest to close out this week, but this time, the main focus of rain and flooding will be on Oregon, AccuWeather meteorologists warn. Some drenching rain will also fall on Washington, which may aggravate high water levels, but it is not expected to be as extreme as recent flooding.
A general 4-8 inches of rain is forecast to fall on western Oregon, with slightly less in the Interstate 5 corridor near Portland. From 8-12 inches of rain with an AccuWeather Local StormMax™ of 16 inches is projected for the western slopes of the Oregon Cascades.
This amount of rain will be enough to unleash moderate to major flooding along both small streams and rivers in western Oregon. A few locations may experience crests close to record levels, such as in the Portland area. Motorists should be prepared for areas of high water and road washouts. Mudslides are also a danger with the storm.
The small streams and the short-run rivers in the Oregon mountainous areas will surge in a matter of hours, adding to the dangers. In the flatter terrain of the lower elevations, the rivers will rise, crest and fall over a matter of a few days.
Rainfall in western Washington will range from 0.50 of an inch to 4 inches, with the greatest concentration in the southwestern part of the state and the southern Washington Cascades. People living along streams and rivers in Washington should be prepared for a new surge of water, but not to the levels experienced in the past week or so, which approached records in some areas.
Due to the frequency and duration of the drenching rain events, the prolonged pressure could result in levee failures.
Crews inspect a breached levee along the Green River in Tukwila, Wash., Monday, Dec. 15, 2025. (AP Photo/Manuel Valdes)
Some drenching rain from the late-week storm will reach part of Northern California, with the greatest concentration from Thursday night to Friday. Enough rain will fall to cause rapid rises on some of the smaller streams and rivers in the mountainous terrain.
California, in general, will face a far more stormy setup from later this weekend through much of the week of Christmas.
While rain and Sierra Nevada snow are needed in California due to recent dry conditions, so much rain may fall to elevate the flooding and mudslides.
Winds from the late-week storm will not be quite as intense as those of the midweek storm. However, some gusts of 40-50 mph are likely in coastal areas, which can easily knock over trees in the saturated soil. Another dose of strong winds will hammer the interior West from later Thursday to Friday.
Colder storms to lead to heavy Cascade snow
The weather setup through this weekend will be significantly colder in the Pacific Northwest when compared to late last week to the start of this week. The lower temperatures will result in much lower freezing levels, which is critical for the amount of snow in the Cascades and how low the snow levels will be.
The colder conditions are great news for ski resorts in the region, which had to deal with rain either washing away the snow cover or making the snow that survived slushy. The colder conditions will also help to ease the avalanche risk.
One major problem will be the accumulation of snow over the mountain passes. Into Friday, 1-2 feet of snow is forecast to fall on Snoqualmie Pass, Washington, the most traveled route through the Cascades in the state along Interstate 90. Stevens Pass is projected to receive 2-3 feet, although the heavily-traveled route in the northern Cascades is currently closed due to damage from the recent storms.
Episodes of additional accumulating snow will occur through the weekend over the Washington and Oregon Cascades, as well as the Olympic Range in northwestern Washington.
Several yards of snow will pile up over the ridges and peaks in the region through the weekend.
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