Aoraki/Mt Cook

Avalanche hazard is rising as a series of cold fronts approach the region.

Time to give thought to what the current surface condition is- a wise man once said, 'todays snow surface could be tomorrows weak layer.'

A number of small loose wet avalanches ran on sunny slopes on the 17th.

Prior to this, there was an avalanche cycle during the storm on the 13th, 14th and 15th, with wind slab and storm slab avalanches on south and east aspects up to size 3 and loose wet avalanches on all aspects below around 1800m.

Late last week about 10cm of new snow fell above 2000m on the Divide. This covers snowfall from earlier in the week that was extensively distributed by gale NW and SW winds, leaving firm windpressed drifts in sheltered areas and slick crusts in more exposed areas. Below around 1800m the snowpack is capped with a hard rain crust. Faceting has been observed in shallow snowpack areas in the Malte Brun range as well as a buried graupel layer that appears un-reactive to snowpack tests. The lower snowpack appears to be well bonded, but we are continuing to monitor crust facet laminates in the lower pack in the eastern part of the forecast area.

Forecast

Showers, possibly heavy, with snow to 1500 metres, clearing in the morning but remaining cloudy.

Wind at 1000 metres

Northerly 45 km/h, dying out in the morning.

Wind at 2000 metres

Northwesterly 50 km/h, easing to westerly 30 km/h in the morning, rising to 50 km/h at night.

Wind at 3000 metres

Westerly gale 70 km/h, easing to 45 km/h in the morning.

Freezing level

1700 metres.

Exposed areas have been stripped back to a slick crust by strong NW and SW winds. Below 1800m there are icy rain crusts. Take an ice axe and crampons( and the knowledge to use them) for any travel above the snowline.

High

• The snowpack structure is well understood.