Issued: Fri, Mar 31, 2017 at 11AM

Expires: Sun, Apr 02, 2017

Above 2,500ft Considerable

1,500 to 2,500ft Considerable

Below 1,500ft Moderate

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

Problem #1: Storm Snow

Distribution: All aspects above 1500ft. New snow is adding up at the rate of about 3-8″ per day. The wet new snow combined with moderate south winds will create cohesive storm slabs, especially on wind loaded Northwest-North-Northeast aspects. The fresh slabs will be tender and ready to move around.

Problem #2: Persistent Slab

Distribution: All aspects above 1500ft. If you dig down about 90cm deep, we have hard slab with lots of weak, facetted snow underneath. There’s also an old rain crust below that with facets above and below (see profile below). Last week, we saw lots of natural and human-triggered slides on these layers. These weak layers have started to slowly strengthen, but loading is increasing and they may re-activate. The added load from new snow today will increase the amount of stress on these weak layers, and some large natural avalanches 3-5ft deep are possible.

 

Problem #3: Deep Slab

Distribution: Isolated, on wind-blown slopes with thin snowpack less than 1m thick. Generally around ridgelines, and anywhere rocks are exposed or thinly buried. All aspects. Elevations above 3000ft. In the Pass zone, there are extensive weak facets at the ground in any areas of thin snowpack. We’re now seeing natural slides on this basal facet layer in areas north of the Pass (see photo). Even in places with deeper snow, there remain trigger points near rocks/thin areas. If you were to trigger a slide on this layer, it would be a deep, wide, hard slab avalanche with deadly consequences. This is a low-probability high-danger situation that is very difficult to manage, so it’s best to exercise caution. Be very careful to avoid rocky trigger points and thin areas. Stick to slopes with a deeper, more uniform snowpack.

Natural avalanche on basal facets this month, north of the Pass area

Recent Avalanche Activity

Last week’s avalanche activity included several D3 slides, running about a meter deep on the troublesome Early March facet layer. This includes some slides that have been remotely triggered from ridgelines, and some skier-triggered slides and close calls.

Recent Weather

Our area received 0.10 – 0.50″ of new water equivalent over the last 24hours with snow levels around 2000ft. Steady light precipitation will continue Friday, Saturday, and Sunday, with 1.00 – 1.50″ of additional water equivalent total. Snow levels will remain around 1500-2000ft with moderate south winds of 10-20MPH.

3-8″ of new snow fell on the 29th above 2000ft. This was mostly in the Lutak Zone.

6-12″ fell on the 27th above 1000ft.

March 19th-23rd brought 8-16″ of snow.

24-36″ of snow fell march 12th-17th.

Additional Info & Media

We’ve been getting widespread reports of sketchy conditions for the last several days. This includes lots of whumphing, shooting cracks, and fresh avalanche activity. Be conservative, and avoid avalanche terrain when possible.

Posted in Chilkat Pass Forecasts.
Erik Stevens

Forecaster: Erik Stevens