Storms to raise risk of avalanches in Pacific Northwest
By
Ryan Adamson, AccuWeather meteorologist
Published Jan 5, 2022 10:20 AM EST
|
Updated Jan 7, 2022 6:42 AM EST
From Oregon to British Columbia, snow fell once again on Jan. 4.
The new year has begun on a stormy note in the Pacific Northwest as frequent rounds of rain and mountain snow have pummeled the region. AccuWeather forecasters say that no change is expected for the next several days, and that could mean an increased risk of avalanches, as well as flooding.
Rain and snow that were ongoing Wednesday increased in coverage and intensity on Wednesday night and continued through Thursday.
"Moisture will continue to flow onshore and produce rain along the coast, including in cities such as Seattle and Portland and Medford, Oregon," said AccuWeather Meteorologist Jessica Storm.
Warmer air will work into the region as well. However, where cold air becomes trapped in valleys, ice will be a concern.
"Snow is anticipated in the mountains, while ice is likely across the Columbia and Yakima valleys," said Storm.
Both temperatures and snow levels continued to rise on Thursday as mild air moved in from the Pacific Ocean. A brief mix with snow to start in Seattle on Wednesday night quickly changed to rain. The snow even eventually changed to rain in all but the highest elevations.
The Washington Department of Transportation reported that Snoqualmie, Stevens, White and Blewett passes were likely to remain closed until Sunday as conditions were too dangerous for their crews to be in the pass areas.
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Several rivers across southwest Washington are forecast to hit their respective record-level flood stage due to the rain and snowmelt, such as the stations along Skookumchuck River near Bucoda and Centralia, according to the United States Geological Survey (USGS).
Yet another system is forecast to move ashore by Friday. Somewhat colder air should allow snow to return to much of the Cascades. The wind is also expected to be an issue at the end of the week.
"Flooding and wind risks, along with the threat of avalanches, can cause dangerous travel across the region, particularly in the passes," noted Storm.
With snow initially followed by rain then potentially more snow in the Washington Cascades, this will make the snow unstable and could lead to the risk of avalanches.
According to the Northwest Avalanche Center, there is currently a "considerable" avalanche danger across a large portion of the Cascades. This means that natural avalanches are possible and human-induced avalanches are likely, according to the North American Avalanche Danger Scale. In Oregon, there is currently a "high" avalanche danger in portions of Mt. Hood National Forest.
There have been six fatalities in the United States due to avalanches so far this season. One of those occurred on Dec. 11 in Washington at the Crystal Mountain Ski Area when a group of backcountry tourers triggered an avalanche in a closed section of the mountain while traveling uphill.
In addition, the system on Friday is likely to also affect areas farther to the south. This will mean a brief return of rain to Northern California and snow in the Sierra. However, both rain and snow totals in California will pale in comparison to what fell in late December.
"Some of the highest rainfall totals are likely to occur in southwestern Washington and northern portions of coastal Oregon," said Storm.
In the Northwest, rain could total 2-4 inches in Seattle and Portland and in Eugene, Oregon. Locally higher totals are not out of the question.
“An atmospheric river from the Pacific Ocean will act as a firehose and produce torrential rainfall, potentially at the rate of 0.50 of an inch to 1 inch per hour at times from west-central Washington to northwestern Oregon into Friday,” AccuWeather Senior Meteorologist Alex Sosnowski said.
The rapid rainfall rates could lead to flash flooding around urban areas and small streams, while also triggering swift rises on some of the short-run rivers that flow out of the mountains.
For storm-weary residents of the region, a respite may finally be in sight. A bit of snow may linger in the mountains on Saturday, but rain will end at the coast. By Sunday, an area of high pressure is expected to take control over much of the West, leading to a dry day across the entire region.
There is some question among meteorologists as to when precipitation may return to the Northwest. Other than a chance of rain in far northwestern Washington on Monday, it appears the break in precipitation will persist through at least Wednesday. However, it is possible that most of the region stays dry through all of next week.
For the latest weather news check back on AccuWeather.com. Watch the AccuWeather Network on DIRECTV, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeather Now is now available on your preferred streaming platform.
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News / Winter Weather
Storms to raise risk of avalanches in Pacific Northwest
By Ryan Adamson, AccuWeather meteorologist
Published Jan 5, 2022 10:20 AM EST | Updated Jan 7, 2022 6:42 AM EST
From Oregon to British Columbia, snow fell once again on Jan. 4.
The new year has begun on a stormy note in the Pacific Northwest as frequent rounds of rain and mountain snow have pummeled the region. AccuWeather forecasters say that no change is expected for the next several days, and that could mean an increased risk of avalanches, as well as flooding.
Rain and snow that were ongoing Wednesday increased in coverage and intensity on Wednesday night and continued through Thursday.
"Moisture will continue to flow onshore and produce rain along the coast, including in cities such as Seattle and Portland and Medford, Oregon," said AccuWeather Meteorologist Jessica Storm.
Warmer air will work into the region as well. However, where cold air becomes trapped in valleys, ice will be a concern.
"Snow is anticipated in the mountains, while ice is likely across the Columbia and Yakima valleys," said Storm.
Both temperatures and snow levels continued to rise on Thursday as mild air moved in from the Pacific Ocean. A brief mix with snow to start in Seattle on Wednesday night quickly changed to rain. The snow even eventually changed to rain in all but the highest elevations.
The Washington Department of Transportation reported that Snoqualmie, Stevens, White and Blewett passes were likely to remain closed until Sunday as conditions were too dangerous for their crews to be in the pass areas.
CLICK HERE FOR THE FREE ACCUWEATHER APP
Several rivers across southwest Washington are forecast to hit their respective record-level flood stage due to the rain and snowmelt, such as the stations along Skookumchuck River near Bucoda and Centralia, according to the United States Geological Survey (USGS).
Yet another system is forecast to move ashore by Friday. Somewhat colder air should allow snow to return to much of the Cascades. The wind is also expected to be an issue at the end of the week.
"Flooding and wind risks, along with the threat of avalanches, can cause dangerous travel across the region, particularly in the passes," noted Storm.
With snow initially followed by rain then potentially more snow in the Washington Cascades, this will make the snow unstable and could lead to the risk of avalanches.
According to the Northwest Avalanche Center, there is currently a "considerable" avalanche danger across a large portion of the Cascades. This means that natural avalanches are possible and human-induced avalanches are likely, according to the North American Avalanche Danger Scale. In Oregon, there is currently a "high" avalanche danger in portions of Mt. Hood National Forest.
There have been six fatalities in the United States due to avalanches so far this season. One of those occurred on Dec. 11 in Washington at the Crystal Mountain Ski Area when a group of backcountry tourers triggered an avalanche in a closed section of the mountain while traveling uphill.
In addition, the system on Friday is likely to also affect areas farther to the south. This will mean a brief return of rain to Northern California and snow in the Sierra. However, both rain and snow totals in California will pale in comparison to what fell in late December.
"Some of the highest rainfall totals are likely to occur in southwestern Washington and northern portions of coastal Oregon," said Storm.
In the Northwest, rain could total 2-4 inches in Seattle and Portland and in Eugene, Oregon. Locally higher totals are not out of the question.
“An atmospheric river from the Pacific Ocean will act as a firehose and produce torrential rainfall, potentially at the rate of 0.50 of an inch to 1 inch per hour at times from west-central Washington to northwestern Oregon into Friday,” AccuWeather Senior Meteorologist Alex Sosnowski said.
The rapid rainfall rates could lead to flash flooding around urban areas and small streams, while also triggering swift rises on some of the short-run rivers that flow out of the mountains.
For storm-weary residents of the region, a respite may finally be in sight. A bit of snow may linger in the mountains on Saturday, but rain will end at the coast. By Sunday, an area of high pressure is expected to take control over much of the West, leading to a dry day across the entire region.
There is some question among meteorologists as to when precipitation may return to the Northwest. Other than a chance of rain in far northwestern Washington on Monday, it appears the break in precipitation will persist through at least Wednesday. However, it is possible that most of the region stays dry through all of next week.
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For the latest weather news check back on AccuWeather.com. Watch the AccuWeather Network on DIRECTV, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeather Now is now available on your preferred streaming platform.
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