Enjoy the clear weather but remember triggering avalanches remains possible on wind-drifted and steep, rocky slopes.
Strong winds have redistributed recent snow into hard wind slabs on lee features at upper elevations that may be possible trigger. Cornices are adjusting to the recent load and may trigger avalanches on the slopes below.
A weak layer of surface hoar buried Jan 11 buried 20-50 cm deep may be found on sheltered, open slopes near treeline in northern parts of the region. Deeper layers from early December and November can still be found in the snowpack and remain a cause for concern in thick to thin areas at upper elevations.
Thursday night: Clear, light variable winds, alpine temperatures dropping to -20 C.
Friday: Sunny, light northwest winds, alpine high temperatures near -15 C.
Saturday: Mainly sunny, light west winds, alpine high temperatures near -16 C.
Sunday: Mix of sun and cloud, light variable winds, alpine high temperatures near -13 C.
There have been no recent avalanche observations in the region. Over the last few days, operators in neighboring Glacier National Park reported several large (size 2-2.5) wind slabs releasing naturally on a variety of aspects (north, east, and south). Two natural cornice failures were reported in Glacier National Park on Wednesday releasing above north-facing slopes. This MIN report from north of the region in Hope Creek reports human-triggered wind slab activity on Wednesday.
This MIN report from the Quartz zone from last week shows a reactive layer of Jan 11th surface hoar on north-facing slopes near treeline. It may be possible to trigger this layer in isolated areas where the surface hoar has been preserved.
Following last week's storm, we received reports of avalanches reaching size 3 in the central part of the region, lending support to the idea that some larger releases may have involved more deeply buried persistent weak layers. Although avalanche activity on these layers from early December and November has been isolated, the possibility exists for large triggers to reactivate these deeper instabilities.
Recent winds have scoured snow surfaces, loaded cornices, and formed stiff wind slabs in alpine and upper treeline areas. A new sun crust may be forming on steep solar aspects, and there here have been reports of surface hoar growing on the snow surface.
30-60 cm of snow buried a weak of layer of surface hoar from Jan 11th. This persistent weak layer is most suspect in sheltered, open slopes at treeline. This layer has produced sudden results in snowpack tests at treeline elevations in areas near KHMR and warrants careful evaluation if you're travelling in the north of the region.
Two deeper layers of surface hoar from December 13th and December 7th may still be found down 100-150 cm. The Dec 7th weak layer consists of a combination of decomposing surface hoar with a crust and faceted snow. Avalanche activity on these persistent weak layers has dwindled in the last week, with snowpack tests results trending to resistant and unreactive.
The lower snowpack is characterized by a notable rain crust from early November that is surrounded by a weak layer of sugary facets. It may still be possible to trigger with large loads in steep, shallow, rocky areas with a thin to thick snowpack.
