New storm approaching.
Backcountry travel becomes difficult in Gale force winds.
With the wind increasing from the West/Northwest expect Wind Slabs to now begin to form on steep East/Southeast aspects. A lot of the snow available to transport is very dry and light so these slabs will potentially form quickly and could grow quite large. Watch for dense pockets of wind blown snow if in terrain above 30degrees, above 1600m.
Steep sunny aspects at mid elevation could soften enough during the day to produce small Loose Wet avalanches. With the freezing level forecasted to rise and with some high cloud developing we could see some 'greenhouse effect' occurring heating up the surface and increasing the hazard. Roller-balling is the first sign that the surface is warming up.
Small Loose Wet reported at Mt Olympus, WSW Aspect, 1800m, 28/07
Small Snowboarder controlled Wind Slab reported at Porters. SE aspect, 1600m.
Coverage is patchy with significant pockets of wind deposited snow all the way through to very thin patches. Upwards of 30cm fell with strong Southwest winds overnight on the 24/07. During the down pour the freezing level dropped to around 1500m leaving cold, dry snow above 1600m and wet snow below this level. A further 10cm fell with light southwest winds 25/07. Possible buried Surface Hoar was recently found within the latest storm snow.
Thursday: Rain, heavy at times about the Divide, spreading elsewhere from afternoon. Snow lowering to 1200m. Gale Northwesterly wind, rising to severe gale in exposed places for a time late morning to early evening. Freezing level 2200m lowering to 1700m in the evening.
Friday: Periods of rain, heavy at times about the Divide until evening. Snow lowering to 600m. Gale Northwesterly winds, changing to Southwesterly gale in the afternoon. Freezing level 1400m lowering to 800m in the afternoon.
Ice axe and Crampons are recommended if venturing out. There are still some hard icy patches especially along ridgelines.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
