Hello
and good morning, this is Toby Weed of the
Current Conditions:
Expect a blustery and rather warm morning, giving way to a
quick-hitting and energetic snowstorm this afternoon. Temperatures are hovering
right around freezing on the highest peaks, and only radiant cooling will have re-built
the surface crust present on the sun-baked snow on most slopes. A southwest wind picked up overnight,
increasing ahead of a cold front that will arrive early this afternoon. The
Campbell Scientific Logan Peak wind sensor is reading average wind speeds in
the mid-thirties range this morning, with gusts as high as 55 mph, and the
thermometer is reading 31 degrees at 9400’.
Sheltered upper and mid-elevation
north facing slopes are the ticket for lingering pockets of soft
re-crystallized snow, and most other slopes are crusty or moist and sloppy
Avalanche Conditions:
Now it’s rather old news, but there were
several human triggered avalanches in the Logan Area backcountry since last
weekend’s storm. (South Cornice Ridge photos). Most recently,
a snowmobiler triggered a small slab on the very steep East Face of
Mount Magog and a skier triggered a small wet slide
north of the mouth of
Yesterday
we noticed frost crystals or surface hoar on shady and sheltered mid and upper
elevation slopes, which could be a nice weak layer for today’s wind slabs to
ride on. Stiff wind drifts probably
formed in some areas overnight with the small amount of available transportable
snow. Strong winds accompanying snowfall
this afternoon will quickly build fresh wind slabs on lee slopes and in fetch
areas. Watch for and avoid obvious drifts on steep slopes. Possible clues include smooth chalky looking
snow, hollow sounding stiff snow, shooting cracks, or whumpfing
noises.
Dropping
temperatures with today’s early afternoon storm will help to alleviate the wet
avalanche problem. But this morning, solar
warming and possible “green housing” will heat up the moist snow in some sheltered
and/or sunny areas, and crusts that re-formed overnight will again soften on
many slopes. Wet avalanches will be
possible on steep slopes in the middle of the day as the surface snow is
re-warmed and becomes saturated. Watch
for roller balling and other recent wet avalanche activity on similar slopes,
and leave or reevaluate your route if the snow on the slope you’re on gets
sloppy.
Bottom Line: There’s a LOW danger on most steep slopes
in the backcountry, and avalanches are generally unlikely, especially in
sheltered and shady terrain. Pockets
with a MODERATE
danger exist on slopes exposed to wind drifting or sun-warmed slopes with
saturated surface snow, and triggered avalanches are possible on some slopes steeper than about 35 degrees in
the backcountry. Periods of heavy
snowfall and strong wind will cause a MODERATE danger of
fresh wind slab avalanches on slopes with deposits of drifted snow. Use
good snow assessment and safe travel techniques to minimize your risks.
Mountain Weather:
The National Weather Service issued
a Snow and Blowing Snow Advisory for the mountains of
Check out the images page for photos of some of
this season’s avalanches.
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.