Two Thumbs
New Zealand · New Zealand Avalanche Advisory · part of New Zealand
Forecast issued 23 hours ago · valid to Jul 22
Published by New Zealand Avalanche Advisory
Current forecast
- High Alpine · above 1,800 m
- 1 · Low
- Alpine · 1,200 m–1,800 m
- 1 · Low
- Sub Alpine · below 1,200 m
- 1 · Low
Highlights
The snowpack in the Two Thumb Range should stay stable with only light rain and snow expected.
Keep an eye on the actual amount of precipitation on Wednesday. The hazard will increase quickly if it is heavier than forecast.
Be prepared for a widespread sliding hazard with lots of rocks in the runouts.
Avalanche problems
Wind Slabs
Unlikely · Size 1
Light snow is expected above 1900m on Wednesday. Although this should not be enough to form large windslabs, there is always the possibility that heavier snow will come than what is forecast. Keep an eye on the amount of precipitation and be prepared to back off steep terrain if significant loading happens.
Even a small avalanche may be consequential with rocks or cliffs in the runout.
Loose Wet
Unlikely · Size 1
Light showers are forecast for lower elevations. If there is more rain than expected, it's possible that enough heat will get through to cause a problem.
Take care to observe the state of the snow and be prepared to avoid steep slopes and runouts if the snowpack loses strength.
Recent Avalanche Activity
No recent avalanches have been reported.
If you see any activity on the Two Thumb Range, please make a public observation. It really helps us to produce accurate forecasts.
Current Snowpack Conditions
Previous gale force wind from the northwest and southwest has left old crusts and rock exposed on ridges and upper elevations.
Deeper snow and good "spring" skiing has been reported at mid and lower elevations on northern slopes.
A widespread rain crust below about 2200m has undergone several melt freeze cycles on sunny slopes
Snow depths in the south are about 70cm, tapering to about about 50cm mid range and 40cm in the north.
The snowpack north of Stag Saddle is not well understood, with no direct observations.
Mountain Weather
Partly cloudy with isolated showers.
Wind at 1000 metres
Westerly 40 km/h, but 55 km/h, dying out in the morning. Westerly 50 km/h developing at night.
Wind at 2000 metres
Westerly gale 65 km/h, easing to 30 km/h in the morning. Westerly 55 km/h developing at night.
Freezing level
1900 metres.
Sliding Danger
The wind has stripped the soft snow back to exposed crusts.
Below 2000m, the snowpack has gone through melt freeze cycles, so any overnight freeze will form a slick crust.
Expect high sliding danger with lots of rocks in the runouts.
Iceaxe and crampons are highly recommended.
Forecast Confidence
Moderate
- We have a good understanding of the snowpack structure and confidence in the weather forecast.
- We are uncertain about forecast precipitation amounts.
- We are uncertain due to variable freezing levels.
New Zealand Avalanche Advisory (NZ Mountain Safety Council)