Periods of heavy snowfall and gale force winds from the North West through to South over the past 36 hours.
Reactive Wind Slab and Storm Slab are likely to exist.
Very careful terrain selection and a cautious approach will be required on Saturday if you wish to stay out of trouble.
Reactive Wind Slab is likely to exist on a range of aspects. However, slopes facing North through to South West above about 1700m will be especially avalanche prone. Avoid ridge line entry points and other steep, unsupported terrain if you encounter stiff, wind driven snow. If in doubt, choose moderate to low angled wide open slopes.
Storm Slab is likely to exist on a range of aspects. Avoid ridge line entry points, convex rolls and other steep slopes if you encounter stiff, storm snow.
Moderate
Back country observations have been hampered over the past 72 hours by North West storm activity and long periods of poor visibility. Control work at Treble Cone on Friday produced multiple Wind Slab avalanches (size 1 and 2) on East facing terrain.
If you see evidence of avalanches in the back country please enter a Public Observation.
A significant amount of snow has fallen over the past 24 hours - 35 cm at Treble Cone. This snowfall has been accompanied by gale force winds from the Westerly half. Prior to the storm which arrived on Thursday 30/7 the snow pack was mostly stable. Having said that, facets and depth hoar (weak, sugary forms) have been found in places. These pockets of questionable strength appear to be quite isolated and are most likely to exist in steep, shady areas (facing East to South). Loading over the next few days will test these areas of weakness.
Saturday - partly cloudy with isolated snow showers. Clearing to a fine day. Light to moderate Southerly winds. Freezing level - 400m rising to 1000m.
Recent snow will have reduced the sliding danger. However, keep in mind that the underlying pack remains shallow especially, at lower elevations. Rocks and icy areas may be lurking below a thin cover of fresh snow.
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
