Issued: Tue, Feb 06, 2018 at 8AM

Expires: Wed, Feb 07, 2018

Above 2,500ft Moderate

1,500 to 2,500ft Low

Below 1,500ft Low

Degrees of Avalanche Danger ?

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

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

We currently have about 4-6″ of recent snow on top of a solid rain crust (around 2″ thick) and a facetting mid-pack. The main concern will be fresh wind slabs at the top of the snowpack. Despite generally low danger in many places, there will be significant areas of MODERATE danger on freshly wind loaded slopes above 3,500′, and in thin/rocky areas where the mid-pack is faceting.

Problem #1: Wind Slab

Location: Wind loaded slopes and cross-loaded terrain features/gullies, above 3,500ft. The upper layer of snowpack contains enough soft snow to make for good riding in protected areas. This softer snow is wind affected in many areas, with north winds whipping it around into recent wind slabs. This will especially be true on high and exposed slopes, and around ridgelines and summits.  It will be possible to trigger wind slabs in this new snow anywhere it is blown in deeper than a few inches. Test slopes and hand shears will be helpful as you judge the danger from slope to slope. Avoid areas of cohesive wind slab.

Stick to areas where the top layer of snow is still soft and protected. Always practice good travel techniques, utilizing safe zones, escape routes, only exposing one person at a time to slopes over 30 degrees.

Problem #2: Persistent Slab

Location: all aspects above 2000ft where the snowpack is thin (< 1.5m deep). Below the upper rain crust, recent cold weather has been slowly faceting (weakening) the layers in the midpack and at the ground in thin, windswept areas. We did get a report of significant weakness within these faceted layers where the snow is thinner, and it’s safe to assume these conditions are relatively widespread wherever the snowpack is thin. Be aware that in these areas, you may be able to trigger pockets of deeper slab. Use extra caution in these areas.

Recent Avalanche Activity

In the last week or so there has been small natural wind slab activity on wind loaded slopes. We’ve also seen human-triggered loose sluffs that have been getting large and swift in steep terrain.

Recent Weather

1-3 inches of snow should fall Tuesday as a weak front sneaks in under the ridge. High pressure will reassert itself Wednesday – Saturday with more clear, breezy, chilly weather. 

 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
36″ 0″ / 0.00 0″ / 0.00 0  light, N 2″/ 0.13 *
Flower Mountain @ treeline
 32″ 0″ / 0.00 0″ / 0.00 0 light, NW 3″/ 0.19 *
Chilkat Pass @ 3,500ft
 20″* 0″ / 0.00 * 0″ / 0.00 * 0 light, NW 3″/ 0.19 *

( *star means meteorological estimate )

Additional Info & Media

If you get out on the snow, send in your observations!


We will be providing an AIARE Avalanche Level 1 Class this winter in Haines, February 23-25, 2018

More info and signup here.

 

Posted in Lutak Forecasts.
Erik Stevens

Forecaster: Erik Stevens