We're back to winter with new snow - Yah!
However this 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.
Initially stick to low angled slopes and low consequence run-outs. Only start punching out after having a good investigation of the relative bonds in the snow pack.
Wind slab danger exists on east to south eastern aspects above 1400m 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 pronounced at higher elevations in the west and north of the forecast area .Avoidance of wind loaded (South east to eastern) slopes is the first management tool.
As we start to 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.
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. And a final flick of small amounts to the north from southerly winds.
Fine, with morning frost, possibly severe in sheltered places.
Moderate westerly winds with a freezing level around 1200m.
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.
High
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
