Wednesday February 27, 2019

Wednesday February 27, 2019
Thursday February 28, 2019
Friday March 1, 2019
Confidence: Moderate - weather models in disagreement with in coming precipitation amounts and a large degree of uncertainty around snow pack structure and stability in the alpine.

Main Concerns

Persistent Slab, Wind Slab - view Avalanche Problems for detailed information.

Travel & Terrain Advice

Dangerous Avalanche Conditions Exist.

When entering avalanche terrain careful snow pack evaluation, cautious route-finding and careful conservative decision making is essential.

Utilize low to moderate angled terrain and choose well supported paths and features.

Avoid unsupported, convex and steep terrain.

Caution on solar aspects during periods of daytime warming.

Avalanche Summary

On Sunday a skier on a south east aspect around 1300 meters triggered between size 1.5 to 2 slab avalanche. The avalanche carried the skier for approximately 100 meters and they where partially buried, equipment was lost but no injuries where reported.

Numerous other reports from experienced practitioners and experienced recreational mountain travelers of weak snow pack conditions during testing primarily focused around the persistent slab problem have been reported. We value and utalize this information and it has been extremely helpful, thanks to all and keep sending in your observations via email forecaster@islandavalanchebulletin.com.

We are seeking public financial support to help VIACS maintain our public safety service. If you’d like donate you can do so at the bottom of this page or if you have questions or ideas please email us at forecaster@islandavalanchebulletin.com.

Avalanche Problems

Persistent Slab

Down 50 to 80 centimeters facets can be found sitting on top of and below a very dense melt freeze crust. This avalanche problem is widespread and can be found on all aspects and at all elevations. This problem is becoming less reactive but still likely to be reactive in shallower terrain to light triggers such a skiers. If triggered this dangerous avalanche problem could produce avalanches to size two.

Wind Slab

Strong South winds and both past new snow fall and available snow have created this avalanche problem. Found on predominately northerly aspects and on isolated protected areas on all aspects. The elevations to find this avalanche problem will be In the alpine and at treeline. Wind slabs are likely to be trigger by light triggers such as skiers and if triggered this avalanche problem could produce avalanches to size two.

Snowpack Summary

A reactive and persistent melt freeze crust with facets both above and below can be found at all aspects and elevations.

Alpine: Surface hoar is likely to have formed and the snow below it remains preserved and is bonding poorly to the old surface. In the upper and mid snow pack a variety of layers can be found and this includes the faceted melt freeze crust. The mid and lower snow pack is well settled

Tree Line: Surface hoar has formed and the snow below is low density and in protected areas surface hoar has been buried down 20 cm and is producing sudden planar failures during light testing. The faceted melt freeze crust can be found down between 50 and 80 cm and is producing resistant planar failures during moderate testing. mid and lower snow pack is dense and well settled

Below Treeline: Surface hoar is has formed and below this snow is preserved and low density. In protected areas surface hoar has been buried down up to 20 cm. The faceted melt freeze crust can be found down between 50 cm and is reactive during moderate testing. Mid and lower snow pack is dense and well settled.

Snowpack Details

SurfaceSurface Hoar crystals size 1-3 mm have formed on all aspects and at all elevations
Upperlow density snow remains preserved of up to 20 cm in sheltered areas this can be found on top of surface hoar. Found between 50 and 80 cm in depth a well established melt freeze crust exists with a layer of facets both above and below it.
MidBelow 100 to 120 centimeters a very dense and well settle can be found
Lowerwell settled and dense

Past Weather

Cold and clear conditions persisted during the last forecast period. Daytime temperatures rose with overnight temperatures descending rapidly to below -12. Winds were generally calm to light from the north west. Solar effect was evident on the surface snow as it became moist and began to settle, likely overnight cooling will create an upper melt freeze crust on south aspects.

Weather Forecast

Wednesday: 2 to 5 cm of new snow, Temperature -2 to -1, Light to Moderate ridge top winds from the North East, Freezing Level to 400 meters.

Thursday: No new snow, Temperature -6 to 0, Light ridge top winds from the North West, Freezing Level to 700 meters.

Friday: No new snow ,Temperature -10 to 0, Light ridge top winds from the South West, Freezing Level to 700 meters.

Posted on Wednesday February 27, 2019 by Jesse Percival

Past Bulletins