Hello and Happy New Year, this is Toby Weed of the
Current Conditions:
The
Avalanche
Conditions:
Yesterday was an active day in the
Strong winds made it down into
lower elevations yesterday and we experienced lots of wind drifting at all
elevations. Cornices hanging over northeast and east facing slopes grew
significantly during the last couple days as winds deposited loads stiffened
snow on the slopes below. In some areas,
wind slabs likely formed on weak sugary surface snow called near surface
facets, and these are likely to still be sensitive to your weight today. Watch for the effects of cross-loading around
terrain features like sub-ridges, rock outcroppings, and gullies. I noticed new
snow drifts at least 3 feet deep at 8000’ yesterday, and I suspect
significantly deeper wind slabs in exposed upper elevation terrain. Last night’s fresh powder may obscure
normally obvious recent drifts or slabs, so don’t only trust your eyes. Pay attention to obvious signs of
instability like recent avalanches on similar slopes, collapsing or woomphing noises, cracking, or hollow sounding snow, and be
willing to reassess your route.
I’m still concerned by the
possibility of deeper slab avalanches in some areas, which will be quite
destructive and potentially deadly.
Suspect weak layers are made up of snow that was on or below the snow
surface in early December. The old
underlying snow is faceted or sugary and weak, and instabilities caused by
overloading slab layers are notoriously slow to heal. In most cases, your weight alone probably
won’t be enough to trigger one of these deep dwelling monsters, but you might
awaken one from a thin spot on the slab. Watch out for steep rocky areas and
slopes with generally shallow snowcover. The weight of a few snowmobiles at one
time on a slope or an overrunning smaller wind slab avalanche might also do the
trick.
Bottom Line:
Today there’s a CONSIDERABLE avalanche
danger on many steep slopes at mid and upper elevations in the
backcountry. You are likely to trigger
dangerous avalanches if you venture onto slopes with significant deposits of
new or wind drifted snow steeper than about 35 degrees. Some natural avalanches are also possible in
areas exposed to drifting from northerly winds.
Avalanche training and experience are essential for safe backcountry
travel.
Mountain Weather:
Looks like a cold night to
celebrate the New Year, with forecast temperatures well below zero. A ridge of high pressure will build into the
region today and strengthen on Tuesday, bringing significant warming to the
mountains and hazy inversion conditions to
General Information:
I will give a free avalanche
awareness talk for teens and their families at the
Check out photos of avalanches in
the Logan Area on our images page.
Go to the Avalanche Encyclopedia if
you have any questions about terms I use in the advisory
I'm very interested to know what
you're seeing out there. Please e-mail observations to me at [email protected] or leave me a message at 755-3638,
especially if you see or trigger an avalanche in the backcountry. We keep all
observations confidential.
This advisory will expire in 24
hours from the posting time.
The information in this advisory is from the U.S. Forest
Service, which is solely responsible for its content. This advisory
describes general avalanche conditions and local variations always occur.