Mountain Safety Collective Backcountry Conditions Report – Friday 5 September 2025

September 5th, 2025
The view to Mt Kosi from Guthega this morning – nice weather for a backcountry tour. Phtoto: Perisher snow cams

Mountainwatch |Mountain Safety Collective

The storm of the winter rounded out August with a bang late last week, delivering 60-80cm of cumulative snowfall that wind loaded more than a meter deep on leeward slopes. As the storm petered out through last Saturday, cold winds kept the surface snow dry, providing excellent quality turns for anyone braving the elements.

This new snow came with multiple reports of windslab avalanches along with evidence that an entire slope on Mt Kosciuszko released at some point during the storm, likely triggered by a cornice collapse. These observations reinforced MSC’s “Considerable” avalanche hazard rating we’d posted during and straight after the storm and our advice to step out cautiously.

Recent avalanche and cornice debris on the eastern slopes of Mt Kosciuszko

Sunday and Monday saw the sun return with phenomenal conditions on offer across the mountains. As temperatures climbed and the winds remained moderate, it was a case of seeking out sheltered slopes that were holding the best quality snow. Some ridge tops were stripped back to rime ice requiring crampons to exit, while alpine slopes became extensively wind-scoured by Tuesday morning, bringing the powder frenzy to n swift end.

The winds have been roaring throughout Wednesday and Thursday this week with snow falling above 1700m since Thursday morning. This should see 5-10cm of new snow by Friday morning, with much deeper wind loading on leeward slopes again.

Jonathan and Rocky admiring their tracks near Thredbo on Monday

As we move towards the weekend, Friday will be the pick with mostly sunny conditions, moderate winds and mild daytime temperatures. The sun will stick around on Saturday, but warmer northwesterly winds will steadily increase through the day. Things turn for the worse on Sunday and Monday as extreme winds accompanied by mild temperatures and rain impacts the mountains. We’re unlikely to see clear weather again until late next week, so pay close attention to updated weather forecasts if you’re planning longer backcountry tours or snow camping missions after Saturday 6 September.

You can keep up to date with free Backcountry Conditions Reports every day by visiting Mountain Safety Collective.