We will be providing an AIARE Avalanche Level 1 Class this winter in Haines, February 23-25, 2018
Above 2,500ft Considerable
1,500 to 2,500ft None
Below 1,500ft None
Degrees of Avalanche Danger ?
Above treeline in the Pass, human-triggered avalanches are possible-likely. There will be pockets of CONSIDERABLE danger on high, wind loaded aspects.
Our current alpine snowpack is characterized thus: 3mm depth hoar at the ground, with a pencil-hard rain crust above, and varying cold wind-packed layers above that. The upper slab has been tender and reactive, sliding on planar crystals above the ice crust.
The takeaway: our snowpack is thin, highly variable from place to place, and generally weak with very poor structure.
A few notes:
- Avalanche season is here. We’ve already had a significant skier-triggered avalanche reported (see below).
- We have an extreme lack of snow so far this season. Total precipitation since October 1st is at 38% of normal. Snow depths are around 10cm at 3,500ft, ranging up to 100cm in wind loaded areas above 5,000ft. Variability is high due to persistent dry, windy conditions.
- Temperatures above treeline are around 0 – 5°F. This has caused faceting of the thin snowpack. These 3mm facets are setting up a weak base to hold up future heavy snows. Keep this in mind as November progresses and snow depths increase. This will likely turn into a deep-persistent slab problem.
Start the season with fresh batteries in your beacon, and practice with your beacon, shovel, and probe.
If you get out on the snow, send in your observations! We will start regular forecasting when enough obs start coming in.
Recent Avalanche Activity
October 28th: First rider-triggered slide reported from the peak north of Nadahini (“Sunny Bunny”). D2 soft slab ran in storm snow from Oct 26-27. Nobody caught or injured. [ SS-AR-D2-R3-S ] South aspect @ 6,200ft.
Small – Moderate natural avalanche activity is occurring during/after storms. So far it has been mostly loose-snow slides, with a few slab avalanches as well.
Alpine temperatures have been hovering around -15°C (+5°F) for the last 1-2 weeks. North winds have been moderate-strong with occasional blowing snow. Another weak storm will bring light snow on Friday, with some clearing possible for the weekend.
|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
|0 / 0.00||0″ / 0.00||0||light, var||6″ / 0.35 *|
Flower Mountain @ treeline
|0 / 0.00||0″ / 0.00||0||light, var||3″ / 0.18 *|
Chilkat Pass @ 3,500ft
|3″ *||0 / 0.00 *||0″ / 0.00 *||0||light, var||2″ / 0.12 *|
( *star means meteorological estimate )