Above 2,500ft Moderate
1,500 to 2,500ft Low
Below 1,500ft Low
Degrees of Avalanche Danger ?
Problem #1: Wind Slab
Tuesday’s storm brought 2-6″ of new snow to this zone, and winds blew hard out of the north Wednesday-Friday, causing wind loading on lee aspects and cross-loading E and W aspects. Human triggered avalanches will be possible with these wind slabs at the top of the snowpack. Test slopes, ski cuts, and hand shears, will be useful tools to evaluate bonding of these slabs and the danger on a particular slope. Always utilize safe terrain and group management techniques.
Problem #2: Deep Slab
Location: All aspects above 1500ft. Confidence: Low Now that the midpack is solidly re-frozen, a strong bridge exists over the main weak layer (old facets 1m deep in the Lutak zone and 30-45cm deep in the Pass). The snowpack was isothermal (0 degrees C) last week through the upper 60cm, but has now dropped below freezing. In most areas, it will be nearly impossible to penetrate the upper frozen ice layer. BUT, in areas where the snowpack is thin, it may still be possible to trigger basal facets or depth hoar which could propagate into areas of deep slab. The likelihood of this happening is generally low, but still possible. Use extra caution to avoid thin rocky areas at the margins of a slab. Be careful when approaching summits, ridges, and other windswept areas. Unsupported slopes will be most likely to slide in this scenario.
Recent Avalanche Activity
During the freeze-thaw conditions over the weekend (March 17th-18th), reports from the field included one human-triggered wet slide at the Pass, and isolated whumphing/collapsing still happening in all zones.
There was a widespread avalanche cycle (March 10th-13th), mostly size D2-D3, a few D4, all aspects. Failure planes appear to have been both above and below the Jan. ice crust, within storm snow, and on depth hoar at the ground in some rocky areas.
19″ of wet snow fell in the Lutak zone mountains Tuesday 3/20 (lesser amounts of 2-6″ in other zones). Sunday will be another nice day before the next storm arrives Monday afternoon. 3-6″ is expected by Tuesday.
|Snow Depth [in]||Last 24-hr Snow/SWE [in]||Last 3-days Snow/SWE [in]||Today’s Freezing Level [ft]||Today’s Winds||Next 24-hr Snow/SWE|
Mount Ripinsky @ treeline
|61″||0″ / 0.00||0″ / 0.00||0||mod, N||0″/ 0.00 *|
Flower Mountain @ treeline
|44″||0″ / 0.00||0″ / 0.00||0||light, NW||0″/ 0.00*|
Chilkat Pass @ 3,500ft
|25″*||0″ / 0.00 *||0″ / 0.00 *||0||light, NW||0″/ 0.00 *|
( *star means meteorological estimate )
Additional Info & Media
If you get out on the snow, send in your observations!