A bump in wind this morning will be the main player in the avalanche game today. There has been a change in the weather overnight and skies are cloudy with a chance for 1-2″ of snow. The winds have just begun to increase from the East and are expected to reach the 25-30 mph range before decreasing this afternoon. Though this is a relatively small bump in wind with little new snow, we do have ample light snow available for transport – especially in the Turnagain Pass area. This is from Friday’s localized snow storm that deposited up to 18″ on Turnagain Pass.
The real concern, however, is how the wind may form slabs that can overload the weak faceted snow which sits underneath the recent storm snow. Friday’s storm snow has become very loose due to Saturday and Sunday’s clear and cold weather (see a couple more obsevations sent in yesterday HERE and HERE). This has decreased the slab properties that were present on Saturday and subsequently no new avalanche activity was seen on the Pass yesterday. Today’s winds however could change that by forming new wind slabs. Any fresh slabs formed have the potential to be quite sensitive to human triggers as they will be be sitting on weak snow.
For anyone getting out today, keep an eye out for areas where Friday’s snow is cohesive and especially where it is supportable to your weight. Watching for recent wind deposited snow, cracking or collapsing as well as quick hand pits are good ways to assess this.
At the upper most elevations, weak snow exists near the ground under the majority of the snowpack (4-6+’ deep). This is responsible for the deep slab problem. There is a low likelihood of triggering a deep slab in comparison to the shallow persistent slab. However, the possibility lingers for triggering a slab that can pull out snow to the ground. Avoiding likely trigger points, especially areas where slabs are thinner, will lower the likelihood of triggering a deep slab avalanche.
This problem is not a concern below 3000ft where the previously water saturated layers have now frozen into a very strong and stable crust layer.
Clear skies and ample sunshine greeted folks that were out yesterday. Winds were calm and though temperatures were in the 10F range, it felt quite warm. Valley bottoms remained cold and in the single digits.
Overnight, clouds have moved in and a trace of snow has fallen with a possible 1-2 inches expected through the day. Winds have just starting to increase this morning and are forecast to be in the 25-30 mph range with stronger gusts from the East. Temperatures should increase as well to 20F at 1,000′ and the low teens on the ridgetops. This change in weather is due to a low pressure center spinning in the Northern Gulf that is just strong enough to send a bit of moisture our way.
This system should exit this afternoon and a return to dry weather and mostly sunny skies are in store for Tuesday and Wednesday. For later in the week, we might start seeing more of a classic wintertime pattern with a low setting up over the Aleutians – which means possible snow in the forecast.
Believe it or not the sun has been able to create a crust on southerly slopes. This was seen mainly in the mid and lower elevations (2,500′ ish).
|01/19/21||Turnagain||Avalanche: Cornbiscuit||Schauer/ Johnston-Bloom Forecaster|
|01/19/21||Turnagain||Avalanche: Sunburst and Tincan||CNFAIC Staff|
|01/19/21||Turnagain||Avalanche: Seattle Ridge||CNFAIC Staff|
|01/19/21||Turnagain||Avalanche: Tincan 2900′ SW aspect below Hippy Bowl.||Kris Marshall|
|01/18/21||Turnagain||Observation: Turnagain Pass Road Obs.||A Schauer Forecaster|
|01/16/21||Turnagain||Avalanche: Tincan Trees||A Schauer Forecaster|
|01/15/21||Turnagain||Observation: Sunburst||Schauer/ Wunnicke Forecaster|
|01/13/21||Turnagain||Observation: Tincan||Johnston-Bloom / Moderow Forecaster|
|01/13/21||Turnagain||Observation: Center Ridge Meadows||Alaska Avalanche School Rec Level 1 Roberts|
|01/12/21||Turnagain||Avalanche: Seattle Ridge/Center Ridge||A Schauer Forecaster|
|Area||Status||Weather & Riding Conditions|