Any avalanching may run faster and further than you expect with a firm crust buried anywhere from 5 to 30cm deep.
From 2000m and below it should be a consideration. Loose wet activity may pick up as the day warms.
Solar slopes will get strong solar input on Monday and the risk of loose wet avalanching will rise on steep sunny slopes. Below 2000m these may run faster and further on the buried crust. Maintain situational awareness of where you are in relation to what might be above you and how heat is affecting the snow.
Storm slab risks are decreasing but care should be taken when entering lines especially on obviously loaded features or unsupported terrain. Take the time to dig and investigate storm snow bonding/layering.
In limited observations on the 16th several size 2 storm slabs were seen on S or SE aspects in twin stream.
A widespread cycle of wet loose and slab avalanching up to size 3 was observed after the heavy snow and rain over night on the 12th. Slab avalanching was mainly around south and east aspects and limited to the storm snow. There was an outlier observation of a much deeper slab on steep unsupported ground high on Mt Darwin NW aspect at 2700m.
Up to around 30cm of new snow fell overnight on the 15th down to about 1200m, with snow as low as 500m. This was weighted toward the SE end of the region, with the Divide getting about 5-10cm. The new snow has generally bonded well to the old surface in limited testing done on the 16th in the Ben Ohau Range. A cold clear night will further improve snow quality and should help break down any rime crust that may have formed in SE cloud. In areas further west with less new snow the old surface may be an issue with the hard rain crust becoming apparent at about 2000m.
In deeper snowpack areas the pack is generally strong. However, in shallow areas especially in the east there is faceting occurring adjacent to crusts. At the moment it is not really an issue but with a heavy load it may awaken.
Forecast
Fine with severe morning frosts, then showers developing in the evening.
Wind at 1000 metres
Light, then southerly 45 km/h developing in the evening.
Wind at 2000 metres
Southerly 30 km/h, rising to 60 km/h in the evening.
Wind at 3000 metres
Southerly 45 km/h, rising to gale 65 km/h in the evening.
Freezing level
700 metres, lifting to 1300 metres in the morning.
Issued: 11:39am Sun 16 Aug
Crampons and ice axe are useful at the moment for alpine travel. The firm rain crust is now buried by snowfall. In steep terrain or where the new snow is shallow this may be an issue underfoot or ski.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
