The majority of avalanche activity this week has been loose dry avalanches. There is widespread evidence of this problem, both natural which occurred during and just after storms, and human triggered.
Some very isolated and small slab avalanches failed during and just after the Feb 2-3 storm. The new snow is struggling to be cohesive enough to act like a slab, and evidence of this is rare.
|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
February 2-3 brought 6-10″ of new snow which sits in old, weak, faceted snow. It will be possible to trigger small, slow moving sluffs on slopes around 35-40° in the newer low density, “light” snow. On slopes 45° and steeper, it is likely to human trigger loose dry avalanches. These will run longer distances, may entrain older, faceted snow, and could produce larger volume sluffs running at moderate speeds.
If you want to avoid this hazard, it’s simple, just stay on slopes 35° and less.
On the more continuous steeper slopes, sluff management will be essential and effective. Getting caught up in a loose dry avalanche may have the potential for tweaking a knee or other similar injury. Be extra cautious when riding above cliffs, or shallowly buried hazards such as rocks where a sluff could catch and carry you into dangerous consequences.
It’s worth mentioning that despite the good snow conditions and appearance of good coverage, there are shallowly buried rocks everywhere. Snow coverage varies greatly, from just a few inches to over 6 feet, often in just a 50 foot distance across a slope. We don’t have the overall coverage you may be used to in February for the Talkeetna Mountains. For skiers and boarders it is not uncommon to hit rocks on every run. Reports from snow machiners on the Willow side have been similar, with better coverage in the basins. A number of people have damaged their machines this season due to low snow coverage.
New snow this week:
February 2-3: 6-10″ at 3-5000′
Overnight: Trace to 1″ at 3500′
Temps at 4500′ have been in the upper teens to 20’s since mid week, with inversions and warmer temps up high. Cloud layers in Palmer have masked the sunshine up at Hatcher Pass. Temps at 3500′ had a low of 4°F and a high of 18°F for the later half of the week. Winds have remained calm to light, mostly from the East.
This morning the temps have dropped into the single digits at 4500′. At 5am Marmot was reporting 6.5°F, and Independence Mine 8°F. At the Palmer airport it’s 10°F at 5:53am with clouds at 1,900 feet.
A short burst of strong winds on Feb 2 was not enough to build dangerous wind slabs, or overload the poor structure of the snowpack, and did not significantly damage the riding conditions. Since then more snow fell and winds have remained calm. Only the very smallest natural slab avalanches in very isolated locations occurred during and just after the recent new snow on the 2nd. As we look forward, pay close attention to the wind speeds and temperatures. Any slab formation will result in increased avalanche danger.
Today skies will have some low clouds very early this morning with better chances for some sun during the daylight hours. The point forecast is calling for Partly Sunny today trending Sunny and clear tomorrow.
NWS Rec Forecast here.
NWS point forecast here.
State Parks Snow Report and Motorized Access information here.