The relentless Gale westerlies will continue to build windslabs in the north of the range.
If you are heading to the south of the area, watch for signs of warming that could indicate a loose wet avalanche problem.
Windslabs will continue to form at higher elevations particularly north of Captains Peak where there is significantly more wind transportable snow.
Reports from the southern end of the range suggest the slabs are smaller.
Take care to identify any wind loaded terrain and consider the consequences before committing to a slope.
The severe gale westerly wind should decrease the risk of loose wet avalanches on Tuesday.
However, warm temperatures and a strong sun may rapidly over heat the snowpack during the heat of the day.
Areas where new snow sits on a firm crust will be of particular concern.
Watch for signs of the snowpack heating like roller balling and be prepared to change plans.
No recent avalanche activity has been reported. However, observations have been limited due to the weather.
If you see any activity on the Two Thumb Range, please make a public observation. It helps us to produce accurate forecasts.
Southern end of range — south of Stag Saddle
Only about 10cm of snow fell about Stag Saddle on Sunday, tapering to less than 5cm at the southern end of the range. This was distributed by severe gale westerly winds into small drifts up to 25cm deep.
Ridge-lines and slopes exposed to the south-west winds, are heavily scoured and stripped back to slick crusts and scree on upper ridges.
Multiple crusts exist in the old snow on all elevations and aspects. Facets (sugary crystals) have begun to form around these crusts at upper elevations, but have not posed problems. At mid-lower elevations, the old snow is well settled and consists of mainly melt forms or round crystals.
Snow depth varies from 40-75cm, with deeper accumulations of 100-120cm in sheltered areas.
Northern end of range — north of Stag Saddle
The snowpack North of Stag Saddle is not well understood.
Fresh snow is expected on Tuesday, which will add to the 30cm of snow has fallen on Sunday, forming windslabs in areas sheltered from the westerly wind.
Prior to this storm, we only have one observation from Monday 10th August from the area around Captains Peak and Mt Toby, reporting only slightly more snow than around Camp Stream or the Richmond Range, with very little old avalanche debris observed. A similar snowpack to the South was reported.
Photos are of the Camp Creek area on Monday
Rain north of Captains Peak, with snow to 1200 metres, cloudy elsewhere.
Wind at 1000 metres
Northwesterly severe gale 90 km/h, rising to severe gale 120 km/h for a time in the morning.
Wind at 2000 metres
Severe westerly gale 90 km/h, but severe gale 120 km/h in the morning and early afternoon.
Freezing level
2200 metres.
Rain has softened crusts at lower elevations. Higher ground could still have a slick sliding surface . A slip or fall on steep terrain could have serious consequences.
Assess runout zones before committing to steep slopes, and carry equipment appropriate for firm alpine conditions, such as crampons and an ice axe. Conservative route selection remains the most effective way to manage these hazards.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
