A North/North West storm is forecast to track across the region on Thursday. The avalanche danger is likely to increase as the storm intensifies.
Be prepared to alter your plans if the weather and snow conditions are deteriorating.
Periods of heavy rain/snow and North/North West gales are forecast. Reactive Wind Slab is likely to form on a range of aspects over the next 24 hours. However, slopes facing North East through to South West above about 1700m will be especially avalanche prone. Minimise your exposure to avalanche terrain on Thursday.
A period of heavy rain is possible before the freezing level drops. The snow pack could become moisture laden and unstable below about 1800m. Put your plans on hold if you find the pack badly rain affected.
Observations have been hampered over the past 24 hours by long periods of poor visibility.
If you see evidence of avalanches in the back country please enter a Public Observation.
A significant amount of snow fell July 22nd - 24th (50 - 60cm in the Albert Burn and at least 30cm further east). Much of this snow landed with minimal wind effect. Prior to the storm which arrived mid last week, 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. Melt/freeze crusts have been forming on solar (North facing) aspects.
Thursday - rain with some heavy falls. Snow lowering to 1000m during the day. North/North West gales rising to severe gale 110kph. Freezing level - 1800m dropping to 1400m in the evening.
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.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
