We're back into an intense storm cycle with periods of heavy loading above 1300m and strong wind redistribution.
Travel in avalanche terrain should be avoided or very seriously considered to utilise low angle terrain with lesser consequences.
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Storm and Wind Slab will be building as the new snow above 1300-1500m comes in and is amplified by wind redistribution from the North West.
Stay away and out of the firing line from loaded south eastern through to southern slopes. Larger avalanches could well run into the sub alpine zone.
With the new snow will come a period of "shedding" from out of steeper terrain on all aspects, but more pronounced on south eastern and southerly aspects.
Plan your trip to minimise time exposure in or under these zones.
Some evidence of old wind slab from early in the week and more recent let loose. Nothin seen in the southern Ben Ohaus or Gammacks that would indicate very recent activity.
Please let us know via the Public Observations link if you see anything of note.
Over 1.5 m of new snow likely fell near the Main Divide between 4–5 July, accompanied by strong northwesterly winds. The freezing level was initially around 2300 m before lowering to approximately 1800 m. Deep wind-loaded deposits are likely in sheltered terrain on east- to south-facing aspects.
From Sunday afternoon, winds shifted to a cold southeasterly. A further 20–30 cm of new snow has probably fallen across eastern regions with more to come, down to about 600m. This shift in wind direction creates a situation with slab possible on basically all aspects. Just a few cm on Tuesday, and again another 10-15cm on Wednesday.
The snow pack in the Gammack range at circa 1800-2000m had a surface rime crust (in some places a second 5cm down, but not everywhere. followed by 50-60cm of decomposing fragments (recent snow) at 1 finger density laying on a strong and supportive melt-freeze crust. No snow structure tests produced results. Still a possibility of buried surface hoar from late June in isolated sheltered pockets, but so far we haven't found any.
Mostly cloudy with occasional rain, heavier and more persistent for a time in the afternoon and early evening. Possible thunderstorms from afternoon. Snow to 1300 metres.
Northwesterlies coming in and rising to Gale or Severe Gale. The freezing level will rise with the winds from 1500m to 1800m.
At snowline elevations and up to around 1800m, or where the wind has stripped slopes North western), expect a very firm icy layer.Ice axe and crampons are essential for travel above the snowline, especially in areas where the rain crust is exposed or only thinly covered by snow.
Low
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
