Backcountry Avalanche Forecast
White Pass
This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways.
Weather Service ID
Click here for complete definitions of the avalanche danger scale.
Forecast
Friday: Avalanche danger becoming considerable above 5000 feet mainly on south slopes and moderate below. Danger decreasing Friday night.
Saturday: Avalanche danger becoming moderate above 3000 feet mainly on south slopes. Danger decreasing Saturday night.
Sunday Outlook: Avalanche danger again becoming moderate above 3000 feet mainly on south slopes. Danger decreasing Sunday night.
Snowpack Analysis
An active weather pattern produced frequently warm and wet or snowy weather the latter half of January. This also generally produced avalanches, consolidation and regional stabilizing of the older portion of the snow pack.
A storm last Sunday and Monday caused heavy rain up to about 5000 feet in the north and 7000 feet in the south. The rain caused consolidation and was followed by varied amounts of snow with new snow varying from little at Snoqualmie to 18 inches at Paradise. An overall cooling trend helped bond new snow and avalanches were limited.
The last, brief storm was late Tuesday and Wednesday. Temperatures remained cool during this storm and most sites near and west of the crest accumulated about 5-15 inches of snowfall. Ski areas from Mt Baker to Mt Hood commonly reported sensitive skier triggered soft slab avalanches up to about 12 inches in depth on Wednesday.
Decreasing winds, clearing and warming began on Thursday.
Detailed Forecasts
Friday
Sunny warm weather should be seen on Friday. The sun is gaining a little power now that we are about halfway from the solstice to the equinox. The main avalanche concern in most areas should be the effects of the sun and warm temperatures on steep sunny slopes. Natural wet snow avalanches should be possible and human triggered wet snow avalanches should be most likely on steep slopes facing the sun. Careful evaluation of wet snow on steep slopes facing the sun should be essential on Friday. Overnight cooling should refreeze wet surface layers and decrease the regional avalanche danger Friday night.
There is a secondary avalanche concern for this area on Friday. Wind transport of recent snow also seems possible to west slopes near some ridges and in the lower passes such as Snoqualmie. Unlike wet snow these layers would persist through Friday night. Use greater caution in the vicinity of wind transported snow which may form isolated wind slab layers on west aspects near ridges and in the lower passes.
Saturday
Lighter winds and sunny warm weather should be seen again Saturday. Wet snow layers should be partly stabilized after Friday. The main avalanche concern should continue to be the effects of the sun and warm temperatures on steep sunny slopes. Human triggered wet snow avalanches may remain possible on steep slopes facing the sun. But don’t forget to evaluate snow carefully on all aspects on Saturday. Overnight cooling should again refreeze wet surface layers and decrease the regional avalanche danger Saturday night.
Remember to continue to use greater caution in the vicinity of wind transported snow and possible isolated wind slab layers on west aspects near ridges and in the lower passes on Saturday.
Sunday Outlook
Light winds and sunny warm weather is expected yet again on Sunday. Avalanche concerns should be similar to but a bit less than Saturday. The greatest caution should probably be needed on steep slopes facing the sun. But evaluate snow carefully on all aspects on Sunday.
Backcountry travelers should be aware that elevation and geographic distinctions are approximate and that a transition zone between dangers exists. Remember there are avalanche safe areas in the mountains during all levels of avalanche danger. Contact local authorities in your area of interest for further information.
NWAC weather data and forecasts are also available by calling 206-526-6677 for Washington, 503-808-2400 for the Mt Hood area, or by visiting our Web site at www.nwac.us.
Danger Scale Legend
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= Extreme avalanche danger | |
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= High avalanche danger | |
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= Considerable avalanche danger | |
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= Moderate avalanche danger | |
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= Low avalanche danger | |
Warning = Extreme or high avalanche danger occurring or expected to occur within 12 hours: at or below 4000 feet in the Olympics and/or WA Cascades; at or below 5000 feet in the Mt. Hood Area.
Watch = Warning conditions expected within 12-48 hours.
Special Conditions = Unusual conditions meriting special attention that do not meet Watch or Warning criteria.
Click here for complete definitions of the avalanche danger scale.