Valid until Wednesday 27 February, 2013.

Confidence: Fair. Timing and intensity of coming weather is uncertain.

Note: Danger ratings above are for areas of highest precipitation (West coast)

Past Weather: The Island Alps saw between about 25 and 80cm of snow from our storm Saturday/Sunday. The snow came with moderate to strong winds from north west to south west and south east. Freezing levels remained seasonal except for a spike to near tree line around mid day Sunday with the approach of our warm front.

Main Concerns: (Avalanche problems)

Storm Slab - Storm slab from significant snow fall exists on all aspects and at all elevations. This slab can be triggered by humans and could produce avalanches from small to at least large enough to bury, injure or kill a person.

Wind Slab - Significant quantities of snow (indeed near biblical on the west coast) combined with strong winds have created widespread wind slab on west through north to east aspects and in cross loaded features at tree line and in the alpine. These slabs will fail naturally during storm cycles and will remain triggerable by humans through the forecast period. Avalanches could be very large.

Persistent Slab - A weak layer of snow exists below our previous storm snow which fell early last week and is now 40 to 80cm down in the snowpack. This layer delivered easy, planar test results on Friday and Saturday. It likely remains reactive though being so deep in the snowpack it will become increasingly difficult to trigger with human loads. Exactly where this layer is found is not that well understood but it appears to be mostly on sunny aspects at tree line and below and may stretch into the alpine on these aspects. Dig around to better understand if this potential problem exists where you are. While a human load is not likely to trigger it, the load of even a small avalanche could which could result in large to very large avalanches.

Weather Outlook:

Overnight Sunday and Monday - Sunday's system will bring a total of 25 to 75cm of snow (greatest amounts on the west coast) by early Monday. Winds moderate gusting to strong from the south east. Freezing level dropping from a high of near tree line to about 900m. A weak ridge of high pressure will bring some sun, cooling temperatures and little precipitation after the storm ends Monday.

Tuesday -Our next system will bring 10 to 40cm of snow (greatest amounts on the west coast). Winds from light to strong and mostly from south east to south west. Freezing levels around 900m.

Wednesday - A weaker system bringing 5 to 25cm of snow. Winds moderate southerly. Freezing level 800m.

Snowpack:

40 to 80cm of storm snow overlies our previous storm snow. Easy shears remained within the storm in testing on Sunday. A weak layer adjacent to a thin temperature crust on sunny aspects is now about 40 to 100cm deep in the snowpack. This layer delivered easy, planar results in tests on Friday and Saturday and likely remains reactive though being so deep in the snowpack it will become increasingly difficult to trigger with human loads. Exactly where this layer is found is not that well understood but it appears to be mostly on sunny aspects at tree line and below and may stretch into the alpine on these aspects. Dig around to better understand if this potential problem exists where you are. While a human load is not likely to trigger it, the load of even a small avalanche could.

Travel/Terrain Advise:

Stay out of avalanche terrain in times of high hazard. Stick to lower angled and/or forested slopes. If you do choose to enter the wind zone later in the forecast period, do so with extreme caution and a good awareness of where there is triggerable wind slab. Be aware that cornices are growing in size and give them a wide berth. Even smaller avalanches can deliver a much heavier load to a slope than a skier. Be aware of these avalanches as possible triggers of a deeper instability as mentioned in the snow pack discussion above. The coming forecast includes the possibility of large to very large avalanches which could run the full length of their path. Keep this in mind if choosing to cross paths even if you are very low in the run out zone.

Prepared by: Jan Neuspiel and The Cain Crew.

Observations or comments? We want to hear them