Fiordland

Avalanche problems

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  Wind slab

  Wind slabs are formed when loose snow in near-surface layers (new snow or old snow) is transported and deposited by wind.

  Avoid wind-drifted deposits in steep terrain.

  Affected aspects

  NorthwestNorthNortheastEastSoutheastSouth
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  New snow

  The avalanche problem is related to current or most recent snowfall. The amount of additional loading by new snow onto the existing snowpack is the crucial factor of the new snow problem. How critical the loading is, depends on various factors such as air temperature, wind or characteristics of the old snow surface.

  Wait until the snowpack has stabilised, or avoid steep terrain affected by recent snow.

  Affected aspects

  NortheastEastSoutheastSouthSouthwestWestNorthwestNorth

Stability

Mon 27th July-Currently the snowpack is starting to become more stable, as temperatures rise after 3 days of very cold temps. In Northern Fiordland an estimated 50cm cm fell from the South to SW above about 1700m between Wed 22nd and Fri 24th July, with rain below this for most of the storm. Temperatures dropped at the end of the storm and snow fell to 600m. Prior to July 24th the snowpack was very shallow, with most slopes below 1700m being below threshold (not enough snow to avalanche). Only slopes at the highest elevations had a layered pack. Mon 21st July - Below around 1800m the thin snowpack had a mixture of rain and snow over the week of 13th to 18th July, culminating in rain up to about 1750m on Saturday the 18th. This snowpack is generally thin, with much of it still below avalanche threshold, and rainsoaked and refrozen. Above about 1800m there has been about 80 or 90 cm fall in northern Fiordland and about 60cm in the south, from a series of westerly fronts over the week of 13th to 18th July. There were warm temperatures on Saturday 18th and this snowpack is now thought to be stable, with possible remaining wind slab at the high elevation areas lee to the west but should be treated cautiously as there have been not observers in the field.

Snow quality

Please see the public observations for some photos from the Darran's on Sunday. Cold dry snow, very wind affected. Some cliff band activity observed. Isolated cracking seen when skinning on wind loaded areas in Homer area. Observations from Milford Track area, Darran's and Routeburn on 20 July -Slick frozen conditions below 17/1800m. Only the highest peaks (North Peak, Talbot, Mt Christina) had some slopes with enough snow to cover terrain features and look wind loaded.

Weather

A front approaches over Wed, expect around 10cm snow down to 1650 over Wednesday.