Stormy and unsettled weather continues for the next 2 days.
The avalanche danger will be HIGH on Thursday. 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 on a multitude of aspects. Strong winds and snow are forecast to continue, but now more from the east, than the west. Wind slabs could now be a couple of metres deep. Natural avalanches are possible on Thursday.
Rain on the snowpack and on new snow can bring on loose wet avalanching, especially as the freezing level fluctuates during the storm. The freezing level goes above 2000mm the west of the park, during the rain/snow. Lower temperatures are forecast for the east. This will increase the avalanche danger.
A lot of rain has fallen up to about 18/1900m. Rain at these lower and mid elevations has created a wet slab hazard. Warm temperatures are forecast for later today will see this become increasingly reactive.
Expect variable surface conditions. Take an axe and crampons if you're exploring when this storm clears.
Moderate
No recent observations due to stormy condtions.
Sunday - 23rd. A size 3 natural avalanche off Mt Talbot, to valley floor. Suspect it to be wind slab
The biggest storm of the winter is happening at the moment, with gale winds, heavy rain and snow and a fluctuating freezing level. Any weak layers in the snowpack at high elevations will be tested. The snowpack is likely getting rain soaked below 17/1800m.
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 developing this morning. Snow lowering to 800 metres about the lakes for a time.
Wind at 1000 metres - Gale easterly 75 km/h, rising to severe gale northeasterly 95 km/h late morning, easing to gale northerly 65 km/h in the afternoon.
Wind at 2000 metres - Gale easterly 65 km/h, rising to northeasterly severe gale 120 km/h late morning, easing to gale northerly 80 km/h in the evening.
Freezing level - 1300 metres but 2000 metres about the fiords, becoming 2300 metres everywhere in the afternoon.
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
