Hatcher Pass Avalanche Forecast
The avalanche danger is MODERATE at mid and upper elevations for WIND SLAB on SOUTHWEST to NORTHWEST aspects on slopes 35º and steeper. The danger is LOW at low elevation.
Conditions are variable, with a variety of crusts to be found on most aspects. There are soft turns to be found on sheltered and low angle slopes but the price of admission is high.
The avalanche danger could rise by the end of the week with snow showers possible throughout the day today and a quick hitting trough expected Friday that could bring 6-12” of snow and a period of strong winds to the area.
Additional snow and loading could create storm slab instabilities, obscure existing wind slabs, and increase the potential to trigger avalanches that fail deeper in the snowpack. Keep an eye on recent accumulations if you’re heading up later this week. New snow will change the game.
One of the few parties out last weekend was able to trigger a sizeable wind slab that pulled out above them. We investigated this avalanche in upper $1000 run and found it had failed on a smooth firm crust.
Conditions are variable. Strong easterly winds have taken their toll and left behind raised tracks, patchy windslabs, and a firm crust on solar aspects.
The crust on solar aspects is firm and encouraging facet growth under it as seen above. Structure on these aspects is poor but wont be a problem until we see significant loading.
|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|
Strong easterly winds on Friday built stiff wind slabs 2-12’’ deep. Periods of moderate to strong easterly winds continued through the last few days and have distributed a variety of thin wind skins on mid and upper elevation SW through NW facing slopes.
Wind slabs will appear as smooth lenses or pillows on leeward or cross loaded aspects. They may sound hollow or crack out from your ski tip as you travel across them.
There are a variety of wind slabs out there to contend with, some are thick, firm, and edgeable, while others are thin, punchy, and grabby. For the most part these slabs are patchy in their distribution due to the overall lack of snow available for transport. On broad or convex slopes these pieces could be more firm, well connected, and easy to trigger.
As with the avalanche we observed yesterday, the possibility exists for these wind slabs to behave more like persistent slabs and break out above you or fail on deeper layers of the snowpack, up to 3′ deep.
As these slabs age they will become more stubborn and unreactive, meaning they could wait to release until you’ve found a thin spot on the slab. The structure exists for these slabs to fail on facet crust layers deeper in the snowpack, increasing the size and consequence of the avalanche.
Recent winds have contributed to the majority of conditions out there. The graph below shows that after their peak on Sunday, winds continued to gust into the 30’s this week and transport what little snow is left.
It’s currently snowing, with a trace to an inch of new snow expected today and continued light to moderate South/Southeasterly winds.
There looks to be increasing chances for more accumulations Friday with a quick hitting trough that will bring a period of strong snow and wind.
With changing conditions be sure to have a look at recent snowfall through the links below.
NWS AVG Forecast here.
NWS point forecast here.
Marmot Weather Station here.
Independence Mine Snotel here.
Frostbite Bottom Snotel here.
State Parks Snow Report and Motorized Access information here.
XC trail grooming report for Mat-Su, Anchorage, and Kenai here.