Complicated weather creates a complicated snowpack.
New snow on Thursday, now it is warming up with possible rain. Rain on new snow creates a Loose Wet hazard.
Stay tuned for any updates throughout this storm.
A rapidly rising freezing level and possible rain mean Loose Wet avalanches likely especially if the forecast rain falls on new snow. With an already very moist snowpack, any rain will increase the hazard with extra load and potential lubrication of the surface below.
around 10-15cm fell to low levels however the temperatures are now on the rise hazard most of the Slabs below will settle and quickly gain moisture. Storm Slabs will still be possible on all steep terrain above 30 degrees above 1900m. This Storm Slab will only exist if the freezing level stays below 2000m.
Wet Slabs occur when the weight of the snowpack suddenly increases and overloads any weak layers on or near the ground surface. This occurs with a very rapid increase of temperatures, the sudden onset of heavy rain or the weight of a smaller Loose Wet avalanche. These Wet Slabs are very hard to predict so avoid any avalanche terrain until the water has time to drain or rain becomes heavy.
Thursday afternoon saw a Loose Wet cycle begin around 14:00. Many Loose Wet avalanches reported in steep terrain around the region 27/08.
Snow coverage across the forecast area is super variable. Up to 150cm in some areas down to rime covered rocks. A very 'spring like' snowpack exists at the moment with a few crusts remaining with patches of moist, windblown snow scattered in sheltered zones away from the Westerly 1/2 winds. Around 50mm of precipitation fell overnight of the 26-27/08 with snow to around 1200m. A warming pattern has begun and if forecast to get very warm on Friday.
Friday: Scattered rain, heavy about the Main Divide and falling as snow above 1300m, clearing throughout the afternoon as fine breaks develop. Gale Northwest winds gradually easing in the evening. Freezing level around 2000m.
Saturday: A few showers. Snow lowering to 1500m at night. Northwest gales. Freezing level around 1800m.
Ice axe and crampons are highly recommended as rain will now turn to ice at low to mid elevations. Ski Crampons will be required if adventuring on skis or snowboard.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
