Last fine day for a bit.
As the weather warms up, Loose Wet avalanches will be the one to watch.
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.
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.
Expect any cold new snow accumulated in steep sheltered terrain could produce small Loose Dry avalanches, especially above 1800m.
Multiple small Wind Slabs triggered with explosives control across the range, 26/07.
Small Loose Wet reported at Mt Olympus, WSW Aspect, 1800m.
Coverage is patchy with significant pockets of wind deposited snow all the way through to very thin patches. Around 25mm of rain fell on the range on the 15/07. 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 found within the latest storm snow.
Wednesday: Mainly fine, with severe morning frosts. Westerly winds rising to gale in the morning. Freezing level 2200m.
Thursday: Periods of rain, some heavy about the Divide. Snow lowering to 1400m. Strong Northwest winds rising to gale in the morning. Freezing level 2200m lowering to 1500m about the divide in the evening.
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)
