New windslabs could build on Monday above about 1800m.
Wet loose avalanches are possible at lower elevations.
Both these problems will be worse at the northern end of the range where snow and rain will add to both instabilities.
Gale north-west winds will build windslabs on south, south east and east facing terrain.
This problem will be worse in the north where fresh snow above 1800m will add to the volume of slab development.
Windslabs could be easy to trigger due to weak surface crystals caused by the recent fine weather.
Take care to identify and avoid recent windloaded terrain.
Warmer temps could bring on a loose wet cycle, particularly in the north where light rain is expected below about 1800m.
Further south the dry wind may keep the problem from developing.
There's a lot of snow on the northern half, so these could get quite large given a big enough slope that rapidly warms.
Watch for signs of rollerballing. Consider what is above you and where you would end up if caught.Be prepared to change you plans if you see signs of significant warming.
A small loose wet avalanches were reported in steep terrain in the Camp Stream area on Saturday. 1800m NW facing slope.
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 Richmond Range.
Two loose dry avalanches ran naturally, on Mt Maude, probably during the storm. They were size 2 on a N aspect. They ran right to ground.
If you see any activity on the Two Thumb Range, please make a public observation. It really helps us to produce accurate forecasts.
We expect the northern end of the range to receive around 10cm of snow on Monday afternoon with rain below about 1800m. Wind loading will be from the NW.
Snow depths in the south are about 70cm, tapering to about about 50cm mid range and 40cm in the north.
At the southern end of the range, a thick, but breakable rime crust makes off piste skiing very challenging, particularly on south facing terrain. This weakens as you head north. It was not observed around Round Hill Ski Area or around Camp Stream. Elsewhere, north facing terrain has developed sun crusts, while south facing holds dry snow, but is much thinner.
The snowpack north of Stag Saddle is not well understood, with no direct observations.
Clear skies with frosts at first, some severe. Cloud developing in the morning, with scattered rain from afternoon at the north end of the forecast area, with snow to 1800 metres.
Wind at 1000 metres
Westerly 60 km/h. Becoming northwesterly severe gale 100 km/h in the morning. Northwesterly easing to gale 70 km/h in the evening.
Wind at 2000 metres
Westerly 60 km/h, rising to northwesterly gale 70 km/h but severe gale 90 km/h in exposed places in the morning.
Freezing level
1600 metres, lifting to 2000 metres in the morning.
Sliding danger is low due to new snow.
Low
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
