Two Thumbs

Incoming wind, and new snow over firm surfaces can quickly build reactive wind slabs.

Firm snow, ice and exposed rocks still present a significant hazard in many areas.

Use careful route selection around ridge-lines, gullies and above rocky runouts.

No new avalanche observations over the past 2 days.

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

Ridge-lines and slopes exposed to the south-west, have been heavily scoured, and mostly stripped back to old crusts, or even bare rocks and scree on upper ridges. Firm crusts and areas of wind-affected snow are widespread, with the most scoured and variable conditions found in the high alpine, and at the southern end of the range.

Sheltered terrain continues to hold soft snow — cold wind-drifted snow can still be found in sheltered bowls that have escaped the southwest gales.

Sunny slopes have been softening from late morning.

Snow depth varies from 40-70cm, with deeper accumulations of 100-120cm in sheltered areas.

Small facets (weak sugary crystals) have begun developing around crusts in the upper snowpack and between layers of old wind slab, particularly on shallow shaded slopes. At present, these are not posing a significant problem. Below the crusts, the lower snowpack is well settled.

Northern end of range — north of Stag Saddle

The snowpack north of Stag Saddle is not well understood, with no direct observations. We expect that deep snow will have accumulated in sheltered areas above 1800m.

Scattered rain, mainly in the morning. Persistent and heavier toward the Divide. Snow to 1400 metres but 1000 metres about Mackenzie Basin.

WIND AT 1000 METRES

Northeasterly 50 km/h, turning westerly gale 65 km/h but 45 km/h south of Mt Hutt in the morning.

WIND AT 2000 METRES

Northeasterly gale 80 km/h turning northwesterly gale 85 km/h but westerly 50 km/h south of Mt Hutt in the morning.

FREEZING LEVEL

1700 metres, but 1400 metres about the Mackenzie Basin.

Firm snow surfaces, exposed ice and rocks are widespread and will present a greater hazard than avalanches in areas previously exposed to the south-west gales. A slip or fall on steep terrain could have serious consequences, particularly above bluffs, in gullies or where runouts are confined.

Take extra care when travelling on hard snow, 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

• We are confident the likelihood of avalanches will increase with the forecast weather.
• We are uncertain about forecast snowfall amounts.
• We are uncertain whether the wind will be enough to form new wind slabs.