Stormy and unsettled weather is forecast for the next 3 days.
About 80mm of precip is forecast during Wednesday morning, with the freezing level rising to 2000m. The avalanche danger will be HIGH on Wednesday. Avalanches could be large and run below the snowline, possibly to valley floor. Avoid avalanche terrain until the stormy weather has passed.
Wind slab has been developing since Saturday. The strong winds forecast to continue and expect the slabs to be where it's sheltered. They could be a couple of metres deep. Natural avalanches are possible on Wednesday.
Rain on the snowpack and on new snow can bring on loose wet and wet slab avalanching, especially as the freezing level fluctuates during the storm. The freezing level goes up to 2000m on Wednesday, during the rain/snow. This will increase the avalanche danger.
Sunday - 23rd. A size 3 natural avalanche off Mt Talbot, to valley floor. Suspect it to be wind slab
Estimate about 70-100cm of snow above 1700m since 21st of August. This has been moved by gale to extreme winds (mainly from the NW), resulting in sublimation and stripped windward slopes and ridges. Any wind loading could be couple of metres deep and has been observed more mid slope. Below 1700m has been rain.
General snowpack description
Below 2000/2200m. Any new snow has fallen on a thick rain crust (14 Aug), with a refrozen wet snowpack underneath. - Above 2000m/2200m. The snowpack is expected to be dry and layered, especially on southerly facing slopes of the highest peaks.
Rain with heavy falls, clearing in the afternoon but remaining cloudy. Snow lowering to 700 metres about the lakes for a time.
Wind at 1000 metres - Northwesterly 50 km/h, changing southeasterly 50 km/h in the morning, rising to gale easterly 70 km/h early afternoon.
Wind at 2000 metres - Gale northwesterly 65 km/h, changing southeasterly 35 km/h south of George Sound in the morning. Becoming easterly 60 km/h everywhere in the afternoon.
Freezing level - 1600m, rising to 2000m in the morning, then down to 1300m in evening
Expect variable surface conditions. Take an axe and crampons if you're exploring when this storm clears.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
