Forty centimetres of new snow fell overnight on a buried layer of surface hoar. On north and east aspects above 1,900 metres, a single skier can release a slab a metre deep. Keep to low-angle terrain, travel one at a time, and let today pass.
02 — Why this layer matters
Surface hoar grows on clear, still nights: feathery crystals standing on end like frost on a fence wire. Buried intact, they hold the new snow the way a house of playing cards holds a book. They do not heal in a day. They heal over weeks, and until then the slope above you remembers every cold night of January. Read the full snowpack profile before you commit to a line.
03 — Snowpack profile · Coire Dubh, 2,040 m, NE
Pit dug Monday 15:40. Extended column test: ECTP 14, clean shear on the buried hoar.
40 cmNew snow, wind-packed on lee slopes
2 cmSurface hoar, buried 31 Jan — the weak layer
35 cmSettled snow, small rounded grains
6 cmRain crust from 18 Jan
70 cmOld base, well bonded
Total depth 153 cm
- Danger
- 3 Considerable
- New snow 24 h
- 40 cm
- Wind, summits
- SW 45 km/h
- Freezing level
- 1,400 m