Hello and good morning, this is Toby Weed
of the
Current
Conditions: A strong winter storm is upon us and the
National Weather Service has sustained a Winter Storm Warning for the mountains around
Avalanche Conditions:
It
was an other active day in the Central Wasatch backcountry yesterday with smallish
but long-running triggered new snow avalanches running far and fast on solid or
crusty bed surfaces (Wasatch action) No recent avalanche activity has been
reported or observed in the Logan Area since last weekend, but the last windy
storm on Valentine’s Day caused some fairly large and widespread natural wind
slab avalanches.
Although
I suspect that yesterday’s heat destroyed the frost crystals and sugary snow on
many slopes especially at lower elevations, this weekend’s light snow fell with
little or no wind, and in some areas it now may be nicely preserving weak
layers that formed on or near the snow surface during the recent high pressure.
(snow photos)
Today,
with high winds and heavy snowfall, freshly formed and forming wind slabs in
exposed terrain will present a significant danger. Strong southerly winds will shift around from
the west and then northwest and new snow will be drifted onto steep slopes and
into lee slope starting zones. Cross-loading
could deposit significant slabs along sub-ridges and in and around terrain
features like gullies or cliff bands. Wind
slab avalanches could run fast and far today on existing hard bed surfaces.
Sluffing
and soft slab avalanches will also become probable during periods of heavy
snowfall once significant snow builds up on steep slopes. Natural avalanches are a possibility as the
storm intensifies, and even relatively small new snow avalanches are likely to
pick up steam and run far and fast, especially on big slopes. So, you’ll want to avoid travel below steep
slopes and stay clear of gullies which might collect and funnel long-running
avalanches.
Bottom Line: This morning
you’ll find a MODERATE danger in the backcountry and wind slab avalanches
are possible, mainly in exposed upper elevation terrain. With heavy snowfall and strong winds during
the day, the danger will likely become much more widespread and the overall danger
will probably rise to CONSIDERABLE.
This means that you are likely to
trigger wind slab or storm snow avalanches on steep
slopes with significant deposits of wind-blown or new snow, and a few spontaneous
natural avalanches may occur in places.
Mountain
Weather: The National Weather Service continued a Winter Storm Warning for the regional
mountains for now through Monday evening. Along with periods of heavy snow, strong
southwest winds will continue into the afternoon and switch around from the
west and then northwest before diminishing. Expect snowfall to continue at
higher elevations through Sunday night and Monday. A high pressure will build in for much of
next week, with another storm likely for next weekend.
Upcoming avalanche class: February
29th-March 1st, Avalanche Basics,
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.