It has now been over two weeks since the last significant precipitation fell on Turnagain Pass. Weak layers that were buried by up to 5 feet of snow in mid March have since adjusted to the load.
Aspects receiving direct sunlight have gone through a steady pattern of melt/freeze. This has resulted in a surface that is crusty when out of the sun and soft after several hours of heating. Aspects devoid of sunlight (on the North half of the compass) have been going through the faceting process. As a result the surface on shaded aspects is becoming more loose over time. Winds from 10 days ago formed stiff wind slabs in the higher elevations. In areas where these old wind slabs exist, the faceting or “re crystallizing” is happening more slowly.
Loose snow avalanches
What this all boils down to is the potential for both dry and wet loose avalanches in terrain over 40 degrees. The volume of these potential avalanches is very low at this point. Despite this, it is still worth being on the lookout for unconsolidated surface snow to move under the weight of a snowmachine, skis or snowboard. This issue becomes more pronounced in high consequence terrain and will have less of an impact on snowachiners than skiers/snowboarders due to the volume. Steep lower elevation slopes hold the potential for slightly higher volume sluffs as temps climb above freezing today.
Cornices
Cornices are starting to show potential for peeling off of ridge lines, as evidenced HERE in the Summit Lake area yesterday. Daytime heating and a lack of wind will combine to amplify the effects of the sun on these giants. As always, minimize your time under or near cornices by giving them a wide berth.
Photo of a cornice “moat” that a skier punched through in the Summit Lake region yesterday (Dan Starr photo)
“Heads Up” conditions in steep terrain
There are plenty of steep slopes with firm surfaces that require a healthy amount of careful and focused travel. A fall in steep terrain could result in loss of control of a snowmachine or be difficult for skiers or snowboarders to arrest. Pay attention to the snow surface and learn how to anticipate surface conditions by the look and texture of the snow before you are on it.
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