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RegisterJan 13th, 2016–Jan 14th, 2016
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The avalanche danger should improve through the afternoon as storm and wind slab instabilities further stabilize. Evaluate wind loaded slopes carefully and choose more moderately angled slopes to minimize storm related avalanche problems.
The WA Cascades will be between storms Thursday and the next system should move inland to have the greatest effect on the southern zones and mainly from about Mt Hood south later Thursday and Thursday night. Only light amounts of new snow are expected in the north and central areas with gradually more storm snow in the south later Thursday and Thursday night at cool temperatures.
The cool weather, expected light winds and precipitation holding off during the day, should allow for a further slow decrease in the avalanche danger through the day Thursday.
Remain cautious, however, in steeper terrain giving storm instabilities time to settle. Look for wind slab mainly on lee NW-SE aspects near and above treeline. Watch for signs of firmer wind transported snow that can indicate wind slab layers near and below ridges.
Storm slabs may be more sensitive to trigger in the Mission Ridge area on sheltered aspects above 5000 feet if recently formed surface hoar was buried intact.
Fair weather over the New Year caused extensive surface hoar and near surface faceted snow that was later buried by light snowfall Jan 3rd-4th. Observations near Blewett Pass, Holden, and for Red Mountain near Salmon La Sac in early January helped confirm the extent and initial sensitively of this layer. However, these layers and a buried surface hoar layer 60 cm down in the Blewett Pass area from mid-Dec have likely gained significant strength due to the mild temperatures over the last week. No recent slides on these layers have been reported.
The North Cascade Mountain Guides were at Washington Pass last Friday and found that the recent storm snow was surprisingly well bonded to the previous snow in spite of the recently buried surface hoar and faceted snow at the Jan 3rd interface. Tests and ski cuts gave no results due to less slab structure of the recent snow.
Avalanche professionals in the Mission Ridge area Sunday and an observation via the NWAC page Monday reported widespread surface hoar growth on northerly aspects above 5000 feet. Light snowfall Tuesday may have buried this weak layer in sheltered non-solar aspects above 5000 feet in the Mission Ridge area. An additional 4-6 inches of snow were received by Wednesday. No further observations were reported Wednesday, other than some pockets of loose-wet slides during daytime warming in the Tumwater Canyon area.