Avalanche Outlook for Saturday & Sunday
Issued Friday, December 27, 2013 at 10:00pm (information provided below expires in 24 hours):
Based on the current weather forecast, avalanche danger for Saturday, December 28 will teeter between moderate and considerable with increased wind speeds and a bit of new snow. Expect thin but reactive new wind slabs (primarily on west to north aspects and cross loaded terrain) and the potential for wind loading to make deeper persistent slabs more likely to be human triggered from the additional stress.
By Sunday, December 29 avalanche danger should decline back to moderate. Wind slabs should be stabilizing and less reactive, but may remain on the brink of failure in some areas. Persistent slab instabilities are relatively elusive and may still be reactive in some areas as well.
Expect fresh wind slabs to form Friday night through Saturday from the remaining loose snow available for transport and whatever new snow comes our way through Saturday morning. Keep an eye out for obvious clues to wind slab instabilities such as whumphing (collapsing), shooting cracks, denser and more consolidated snow, and snow that looks fat, “pillowy” or sounds hollow (denser snow on top of less consolidated snow).
Weak and loose faceted grains (weak layer) on top of old melt-freeze layers (bed surface) – in some places shallowly buried and in other places deeply buried – with cohesive layer (slab) above, is a widespread snowpack setup found throughout the Front Range and Eagle River area Chugach Mountains. While larger avalanches that could result from this setup are much less likely to be triggered than fresh and smaller wind slabs, this setup has the potential to create the most inherently dangerous avalanches. If you are in avalanche terrain with consequences, dig and assess the situation for yourself!
Saturday is forecast to be cloudy with light snow tapering off in the morning, moderate upper elevation winds, and temperatures in the upper teens to low twenties.
Clouds are forecast to be on the decrease Sunday, becoming partly cloudy with light winds and temps in the lower twenties.
Please contribute your observations and share them with the AAC if you get out in Chugach State Park!