A change is in the cards with new snow.
Any new snow will be landing on a very firm surface, so we will need to treat the new/old bond with caution and plan our route accordingly.
Wind slab danger exists on east to south, and now northern aspects above 1400 m.
New snow will be on top of a potentially very firm surface. This bond will need to be investigated. This concern is likely to be more ponounced at higher elevations in the west and north of the forecast area, where it could be more of a CONSIDERABLE hazard.
Avoidance of wind loaded (South east to eastern) slopes is the first management tool.
With a new storm inbound, we can expect to see small Loose Dry "sluffs" out of steep terrain on all aspects above 1600m.
Later on Saturday, when, fingers crossed, we see the sun, there will be a period of loose wet avalanching.
This will mainly be from steeper terrain affected by the warming affect of the sun.
Stay clear of such terrain and avoid picnicking under such.
High
Several natural small slabs occurred on east to south eastern slopes close to ridgecrest on Ohau snow fields on the 24th. Expect similar natural events in the rest of the forecast area, potentially larger closer to the Divide.
Please use the Public Observations link if you see anything interesting.
Approximately 15–20 cm of new snow fell above 1850 m between 13–14 July, accompanied by severe NW winds that later shifted to the SW. In exposed terrain, the strong winds stripped the new snow back to the ground or to slick rain crusts.
Wind loading created pockets of dense wind slab on east through south aspects in isolated pockets, but can be 30-40cm thick. They so far haven't been reactive to tests.
Below 1850 m, precipitation fell as rain, forming a widespread rain crust on all aspects.
Expect 10-15cm new snow on top of this firm layer on Thursday, mostly above 1800m and 5-10cm on Friday to around 1200m. Strong winds will have redistributed this the mostly eastern and south eastern aspects.
Rain easing to showers in the morning, clearing to fine in the evening. Snow to 800 metres in the morning, but 400 metres around Mackenzie Basin, affecting higher roads and passes.
The previous Gale north wests winds are likely to swing to the south and ease. And just a few more cm's of snow.
Firm snow conditions are present on west-facing slopes near ridgelines and at lower elevations where a rain crust exists. These hard surfaces may present a sliding hazard, particularly on steep terrain and may be cunningly hidden under new snow.
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
