Aspiring

Avalanche problems

• 

  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

  EastSoutheastSouthSouthwest
• 

  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

  NortheastEastSoutheastSouthSouthwest
• 

  Wet snow

  The avalanche problem is related to a weakening of the snowpack due to the presence of liquid water. Water infiltrates the snowpack due to melt or rain.

  Good timing and trip planning are important. Consider avalanche runout zones.

  Affected aspects

  WestNorthwestNorth

Stability

Between the 23rd and 24th of July, 50- 60 cm of new snow fell above 1800m. Below 1800 m, a significant amount of rain has soaked the snowpack before temperatures started to cool early Friday morning and finished with about 20cm at around 1300m. Strong north-west winds may have redistributed much of the new snow in exposed areas during the storm and then again by south-west winds early Friday. Before this, gale westerly winds mostly stripped west aspects back to hard ice or rock and loaded east aspects above 2000m with 1-2m of dense snow. At around 1800m the snow depth was around 50-70cm and was capped by a supportive rain crust before the last storm. Although the pack appears consolidated, the Aspiring region is very large, and there is still very limited data. Caution should still be taken, particularly in steeper, more extreme terrain where unknown weaknesses may exist.

Snow quality

On the 25th, around Mt Armstrong, multiple smaller (sz 1) natural wind slab activity was found across NW and W aspects around Tt Armstrong above 1600m. Further south, around the Grant Glacier, a size 2 avalanche was triggered by ice fall at 2000m. This appeared to have stepped down through multiple storm layers. A few other storm and wind slab avalanches were observed to have run out of the last storm on southeast aspects above around 2000m. A size 1 wind slab was also triggered at 2100m also on a southeast aspect by a skier on Sunday also near the Grant Glacier. If you see any recent avalanche occurrences or have any relevant snowpack information or photos, you can share them via the Public Observations link on the NZAA home page.

Weather

Forecast for TuesdayCloudy periods, with isolated showers developing towards evening.Wind at 1000 metres Light.Wind at 2000 metres Southwesterly 30 km/h, turning to northwesterly 40 km/h in the evening.Wind at 3000 metres Southwesterly 45 km/h, turning to northwesterly 50 km/h in the evening.Freezing level 1700 metres, lifting to 2100 metres in the evening.Issued: 1:03pm Mon 27 Jul