Confidence: Fair - The West Coast of Island may receive more snow than other areas Tuesday; and if it does the Danger could go to CONSIDERABLE in the Alpine. This is true if any area gets 20 cm or more of snow Tuesday. Note: Mt Cain has already had 5 cm snow since it rained last weekend.

Past Weather: On Friday and Saturday AM the Island Alps saw  20 mm rain on the East side and up to 50 mm rain over on the West Island. The wind was not really a factor. Freezing levels rose in most places to mountain tops before cooler temperatures set in later Saturday (this was more so on the West and North island). Temperatures rose well above freezing in the sun today (Sunday) on the East Island but remained below freezing under cloud in other areas.

Main Concerns: (Avalanche problems)

Wind Slab - The higher elevations in the West and North Island areas may have some wind slab forming with dry weather winds from the NW NE or Northerly directions, loading South South West and South East aspects in the Alpine.  Human triggering is possible natural triggering unlikely. Avalanches could range from small to just large enough to bury, injure a person. Tuesday this Wind Slab may continue to build.

Weather Outlook:

Monday - Clear and cloudy periods with no real precipitation expected.  Winds light gusting to moderate from the North North East. Freezing level Surface to 1000m.

Tuesday - Snow above 800 m, accumulations of 10 cm to 20 cm (West island). Winds light gusting to moderate from North North East. Freezing levels from 500m morning to 1000m with the snow fall in the day, then dropping to below 1000m by end of day.

Wednesday - Sunny periods are possible with a trace of snow too. Winds variable to light from North East to East. Freezing levels Surface rising to 1000m and dropping back to surface.

Avalanche activity - Numerous natural Pin Wheels and Skier Cut Loose Wet surface sluffs were reported on the East Island. Limited Alpine observations made.

Snowpack

A deep coastal snow pack has now undergone dramatic settling, compaction and surface renovations. The surface is a crust with moist snow below that is refreezing 60 cm down. Some areas have new snow on the crust. Watch for breakable crusts on colder aspects and higher elevations. My outlook for this early week; with two cold clear nights and showers this could deposit surface hoar and or light new snow over the crust, prior to Tuesday's snow fall.

Travel/Terrain Advise:

Caution a slip and fall hazard may exist.

It might be a good time to go climb. Watch for breakable crusts on colder aspects and higher elevations and variable surfaces.  Re enter the Alpine with caution, confirm refreezing and bonding in the upper snowpack.

Monday - Watch for new Wind Slab in the Alpine which could be redeposited from North North West or Easterly Winds.

Tuesday and Wednesday - additional snow may be unstable on the crust and more Windslab may form.

Prepared by: Niko Weis.

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