A windy storm is here for the weekend.
Rain on snow quickly increases the Loose Wet hazard.
An elevated freezing level and possible rain will react quickly causing roller-balling first then possible Loose Wet avalanches, on all aspects and elevations. Be aware of this hazard if traveling uphill in these areas.
Wind Slabs are more dense and contain smaller snow particles due to being tossed around and beaten up by the wind. These Wind Slabs will be found mostly on Southeastern1/2 aspects. The stronger the wind, expect to find Wind Slabs lower down the slope from the ridge and in very sheltered zones. Cornices indicate wind direction and could possibly grow quite large with the forecast weather. Watch for denser, hollow sounding pockets of freshly deposited snow on steep slopes above 30 degrees.
Any unreactive slabs lingering in the snowpack could be triggered by the sudden onset of rain. Rapid overloading of the weaker structure around could increase the likelihood of Wet Slabs in untracked terrain on most aspects at elevations above 1600m.
Sunday: Scattered rain clearing in the morning to partly cloudy with isolated showers. Gale Northwest winds easing and turning Westerly in the afternoon. Freezing level 2100m lowering to 1200m in the morning.
Monday: Fine, but becoming partly cloudy with isolated showers in the morning. Strong Westerly winds turning Northwest and rising to gale in the morning. Freezing level 2000m.
Ice axe and crampons are highly recommended. Ski Crampons will be required if adventuring on skis or snowboard.
Low
Nil in the past 24hrs.
Snow coverage across the forecast area is super variable. Up to 150cm in some areas down to rime covered rocks. Warm temperatures will have settled the upper pack somewhat, almost creating a spring like snowpack leaving a firm surface after overnight freezes. Around 10cm of cold dry snow fell on the 15th and 16th August. This fell onto a very firm surface. Moderate Southerly wind pushed a lot of this snow onto North and Western aspects. Soft cornices were observed on Western aspects above Tarn Basin 16/08. Cold temperatures are creating a weaker layer underneath this new snow however this is not widespread in the forecast region. This is a layer to monitor over time to see which way it will go.
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
