Turnagain Pass

A beautiful day yesterday saw many folks out enjoying the backcountry. Slowly but surely people are testing the steeper slope angles – but not the real steeps, yet. This is due to an 11-day old and stubborn layer of buried surface hoar 2-3′ deep in the snowpack.

In the Girdwood Valley, however, things were a bit different yesterday where two skier triggered avalanches occurred. This was in the Raggedtop zone and, interestingly enough, in the same spot. No one was caught, luckily. You can read the account HERE and watch the video. The second avalanche took out the entire first avalanche as the fourth person in the group skied down a very similar line to the first three. The weak layer is suspected to be facets near the ground. Although this is a different weak layer than the buried surface hoar at Turnagain Pass, it is still a “persistent weak layer” that sits under a slab and the same caution applies.

Photo below: The second avalanche triggered on Raggedtop by the fourth skier down the slope – seen on the right. (East facing ~4,000′)

For today, forecasted cloud cover and strong winds may deter travel in the upper alpine, but if you do decide to get into bigger and steeper terrain, it will be crucial to manage yourself and your group appropriately: 

Avoid trigger points, such as steep rollovers, rocky zones and areas where the snowpack is thin
Only expose one person at a time
Utilize islands of safety
Have an escape route planned, and communicate plans and decisions effectively

It is getting to the point where the buried surface hoar is harder and harder to trigger in our test pits and time is on our side. Chances are steep upper elevation slopes can be ridden without incident, but there is still a chance you could pull out a slab too.  Slabs have the potential to propagate across slopes and carry enough volume and speed to injure and bury a person.

Both old and fresh winds slabs will be something to watch for in areas above treeline. Old wind slabs 8-12+” thick, that formed during Christmas Day’s strong Southerly winds, may still be touchy where they are sitting on weak faceted snow (Summit Lake area or Girdwood Valley).

Today the winds are forecast to become strong from the East – averages in the 30-40mph range – by the afternoon. In this case, watch for new wind slabs forming on leeward slopes. There is not a lot of loose surface snow available for the winds to transport, but enough I suspect to form 4-10″ slabs in some areas. Additionally, the wind direction is East as opposed to South, as in the Christmas event, that will possibly provide the wind additional loose snow to work with.

Watch for plumes off peaks today and steer clear of slopes seeing current wind loading. Areas below 2,500′ will not only have less wind effect and lower avalanche danger, but will harbor the better riding conditions as well.