A warming trend begins later on Monday. Expect loose wet avalanching hazards to increase as recent cold snow loses strength.
Loose wet avalanching should be expected over Monday as the freezing level climbs. Below 1800m new snow may overlie a rain crust which will act as a good bed surface for any avalanching-they could run further and faster than expected. Watch where you park up for lunch and be flexible in your planning if the day turns out warmer than expected.
An estimated 100cm of new snow has fallen about the Divide, with around 40cm to the east as of Saturday morning. Winds were strong to gale NW but eased back over Friday, and finished much colder southerly. A change to very cold southerly winds will have shifted loading onto northerly aspects. Any storm snow instabilities should be healing and early observations tend to support this. Be sure to treat each slope with respect and check the bond within the new snow and to the old surface.
A natural avalanche cycle has taken place. Many size 2-3 slab avalanches were observed to have run probably during the storm. A loose wet cycle was also underway to size 1 as the day warmed up on Sunday.
Around 100cm of new snow has fallen about the Divide since late Thursday and into Friday with 50cm at Mueller hut (1800m elevation), and around 60cm in the Liebig range. 20-40cm of new snow is expected to have reached eastern areas in the Cass. Winds were strong or gale NW initially but eased and turned much colder southerly. Snow has fallen to valley floor. Reports from guided ski parties suggest a 'right side up' trend in the storm snow and a reasonable bond. This new snow overlies snowfall from earlier last week that was extensively distributed by gale NW and SW winds. Below around 1800m the older snowpack was capped with a hard rain crust which will provide a good sliding surface for any avalanching, (loose or slab), to gain momentum. Faceting has been observed in shallow snowpack areas.
Forecast
Fine to start, then cloud increasing.
Wind at 1000 metres
Light.
Wind at 2000 metres
Westerly 35 km/h.
Wind at 3000 metres
Southwesterly 35 km/h.
Freezing level
1200 metres, lifting to 1800 metres at night.
Issued: 12:34pm Sun 26 Jul
Exposed areas could be firm. Firm crusts may be hidden under new snow below 1600m.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
