Friday February 16, 2018
Cornice Fall, Wind Slab
Travel & Terrain Advice
Minimize overhead exposure during periods of heavy loading from forecast new snow and moderate south wind
Avoid freshly wind loaded features
Identify and avoid all old avalanche debris and cornice debris. All hiding under a thin cover of new snow.
Reports that new snow wind slab avalanches became touchy to skier triggering following the new snowfall Tuesday night. These small avalanches size 1 where located in isolated protected areas on north aspects and failed on the melt freeze crust.
Cornices will continue to grow on north aspects at both the treeline and the alpine. If triggered these could produce an avalanche big enough to bury injure or kill a traveler. Take the time to identify these features and ensure a wide berth when travelling either above or below them.
New snow and moderate south west wind will form hazardous winds slab ( size 2) on north aspects and will be found in both the alpine and at treeline. Expect these avalanche to be touchy to light triggers such as skier traffic and when triggered will run fast and far.
Past new snowfall has been highly wind effected and the prevalent surface condition is melt freeze crust, expect this hard crust to bond poorly with new snow forecast for the coming weekend. A few periods of cooling and clearing promoted surface hoar to form both at the surface of the melt freeze crust and within the new snow. Suspected that in isolated protected areas its been buried. Below the melt freeze crust well settled and well bonded snow can be found.
|Surface||Variable surface conditions from pockets of new snow to very hard melt freeze crust|
|Upper||dense and hard melt freeze crust|
A moderate storm has deliver in northern regions of the forecast area up-to 15 cm of new light snow. As the storm tracked south , precipitation amounts became less with the most southern portion of the forecast region receiving as little as 3 cm. The winds have been from both southerly and northerly direction with moderate wind transportation of snow. Temperatures have generally been cool in the alpine and at treeline.
Cool temperatures will continue as a new storm front Friday night will bring moderate south west wind and between 10 and 30 cm of new snow. Beginning Sunday, a ridge of high pressure will bring to the region, cool temperatures, light north wind and clear skies.
Friday 5-10 cm new snowfall temps -3 to 0, winds moderate Sw, freezing level 700 m rising to 1100 m mid day.
Saturday 10-30 cm snowfall temps -3 rising to 0, winds moderate Sw, freezing level 400 m rising to 1200 m mid day.
Sunday no new snowfall temps -8 to -12 winds light to moderate Nw , freezing level 0 m.
Posted on Friday February 16, 2018 by Jesse Percival