Arthur's Pass

The storm continues tomorrow. High avalanche hazard. Avoid backcountry travel; large avalanches are expected to run to the valley floor.

Keep out of runout zones, including tramping terrain and valley floors.

A natural avalanche cycle is expected to have occurred during the storm.

Park user observations provide important information. Please help us.

If you see anything, please report it in the public observations section of the NZAA website.

Up to 370mm of rain has fallen in western areas of the Park since Friday night, plus snow to Arthus pass village. Thus has been accompanied by fluctuating freezing levels over the last 5 days. Most areas below ~2100m will have received a snow-rain-snow combination, followed by snow falling to ~900m on Thursday. Snow totals remain to be determined once the storm concludes but the threshold for avalanches in western areas of the Park close to the divide is probably around 1500m, tapering to the east. A series of rain on snow events over the past weeks mean rain percolation channels will be well established in the snowpack below ~1800m and new channels will be forming to the highest elevations during this storm's heavy rain precipitation. Strong to gale winds from the northerly half will have formed windslabs on south- through east-facing slopes and around terrain features. The underlying snowpack was well consolidated prior to the storm and once drained is unlikely to hold deeper layers of concern for avalanche hazard.

Rain with heavy falls, and snow to 1600 metres, easing to a few showers in the afternoon. Winds Severe gale northwesterly 120 km/h, easing to westerly gale 70 km/h in the evening. Freezing level 2000 metres, lowering to 1600 metres at night.

Conditions are changing. Low sliding hazard at present.

Moderate

• We are uncertain about forecast precipitation amounts.
• We are uncertain about forecast snowfall amounts.
• We are uncertain due to rapidly changing freezing levels.