Avalanche Forecast

High

One size 1.5 natural avalanche (wind slab) was observed in the Commonwealth area on a NE aspect. Also a report of a 0.5 wind slab that was remoted on a suncrust. It appears that both are wind slabs from the winds in the last 24hrs.

One skier triggered avalanche size 3 occurred in Tent Bowl on Sunday. The avalanche was triggered after the fourth turn and the skier was carried down with it and buried up to their neck, but without any injuries. The avalanche depth varied from thin to thick with evidence of the March 20 interface, the February 2 crust, the basal facets and the ground. Some of the blocks were the size of a Ferrari. Please see the MIN report at https://avalanche.ca/map?panel=mountain-information-network-submissions%2F3a547b44-ea29-11ee-97c1-0a58a9feac02

Quite a complex snowpack for this time of year. Let's break it down starting from the top of the snowpack and working our way down:

• In general, there is about 10-20cm of settled overlying the March 20 temperature crust. Generally this snow is well bonded to the crust except on steeper terrain where you could still sluff it while skiing. Any terrain that is tipped slightly to the sun has a sun crust on it in the morning and will soften when the sun comes out. The forecasted 5cm of snow will freshen things up.

• The March 20 temperature crust (down about 20cm) is anywhere from 1-10cm thick and can be mostly found below 2400m on North aspects and to mountain top on solar aspects. Some areas do not have this crust and is not providing any bridging.

• The February 2 crust is down about 60-80cm and has started to break down with facets on top and below it. This layer is not to be trusted anymore in terms of bridging any deeper instabilities

• The basal facets make up more than half of the snowpack and are clearly visible when you dig a snow pit. Any avalanche that is triggered in the upper snowpack could easily step down to this layer. If this happens, one is looking at a full depth avalanche to ground.

The depth of the snowpack is quite variable with thin to thick areas of snow. The Tent Bowl size 3 avalanche that was skier triggered a few days ago is a classic photo of thin to thick areas. In this instance, the avalanche appears to have been triggered from a thin area that went full depth and is right beside a thick wind loaded feature. With everything going on in the snowpack, a more conservative approach seems reasonable. The bigger ski lines and larger features are best left alone in these conditions.

Thursday will be mostly cloudy with light flurries and 2-4cm. Winds are expected to be around 40km/h from the SW at ridgetop. Freezing level will be 2200m with a high of -3c in the alpine.

Be aware that when the sun does come out it packs a punch at this time of year and snow stability will quickly deteriorate on the solar aspects. Thin cloud can also lead to a "Greenhouse Effect" that can make the upper snowpack moist and unstable. Lots going on in Spring!

More details can be found in the Mountain Weather Forecast.

• Conditions may have improved, but be mindful that deep instabilities are still present.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.