The new snow needs time to settle and gain strength.
Large windslabs with unknown bonding are expected on north facing terrain. Safe travel will depend on solid terrain and snow assessment.
There is a high degree of uncertainty due to limited field observations. A conservative approach is recommended.
A clear day is forecast for Friday, however, wind loading may continue throughout the day adding to large drifts that have accumulated during the last few days.
We expect slabs to extend a long way down slope. They will involve a lot of snow and could be triggered by a single persons weight.
It would be best to give these slabs more time to bond. Avoiding windloaded terrain is recommended.
Storm snow is settling and gaining strength, particularly at lower elevations. Lurking weaknesses may still be possible to trigger on Friday. Evaluate snow carefully and consider the terrain and consequences before committing to avalanche terrain.
The sun will come out on Friday and at lower elevations things will warm up.
Loose snow activity is possible in the heat of the day on sunny slopes.
There's a lot of snow on the northern half, so these could get quite large given a big enough slope that rapidly warm.
Timing is everything. Anticipate where the sun will be baking the snowpack. Watch for signs of rollerballing. Consider what is above you and where you would end up if caught.
5 slab avalanches were triggered naturally, possibly by cornice fall near the end of the storm on Wednesday. They were up to size 2 (large enough to bury a person) on a NW aspect at 2100m on the Western side of the range.
There have been limited observations of terrain post storm, so other avalanches are possible.
If you see any activity on the Two Thumb Range, please make a public observation. It really helps us to produce accurate forecasts.
Total amounts of new snow varies across the region, with the heaviest falls in the south and west of the range.
120 cm of light snow was reported in the Camp Stream area. 70cm of dense snow at Round Hill and Dobson.
Fox Peak only received 40cm. We expect the far north end of the range to also have around 30cm.
In exposed places, this snow has been distributed by gale southerly winds with deep drifts expected on northerly facing terrain.
The new snow is settling fast below about 1600m with slightly warmer temperatures on Tuesday afternoon.
Areas of morning cloud, clearing to fine by afternoon.
Wind at 1000 metres
Southerly 30 km/h, dying out in the afternoon.
Wind at 2000 metres
Southeasterly 55 km/h, easing to 35 km/h in the morning.
Freezing level
800 metres, lifting to 1200 metres in the afternoon.
Sliding danger should be low due to new snow.
Low
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
