1. Danger level 4 – « backcountry »
(16.-) 17./18. – (20.)
Landschaft Davos, Schweiz

2. avalanche bulletin 17.12. for 18.12.
General
20 to 40 cm new snow during the last 24 h (30 to 50 in 2 days) (morning)
temperature at 2000 m: minus 12 degrees
strong to stormy NW-wind
weak old snowcover, surface hoar, locally much wind drifted snow
Short term evolution
30 to 50 cm new snow in the next 24 h
temperature at 2000 m: minus 14 degrees
strong NW-wind
Avalanche danger forecast
The avalanche prone locations are primarily on steep slopes of all aspects above approximately 1800 m. Many medium spontaneous, partially large avalancehs are to be expected. Exposed parts of transportation routes can be endangered. Between 1200 m and 1800 m the avalanche danger is considerable. Aside secured ski runs, the situation is very dangerous.

3. 1
HS ca. 30cm 2

4. snowcover Profil 1 – 19.12. 2295 m, E, 33° (see also overview map)
Location: Very little slope on a dome, typically for wind
drifted snow. The wind drifted snow is some days old. Some cm new snow. Well bonded layers in the middle of the snow profile, underneath weak old snowcover. Wind drifted snow: Only adjacent to the ridge line, only some. Danger signs: Many fresh and some days old avalanches in the
Parsenn ski area, no wumms and no cracks. Snowsurface: undulated, skipen 40cm, bootpen 60cm.
Rutschblock: 1. Jump with skis, fracture at the transition to a
well bonded layer of wind drifted snow. No more fractures at all. Estimation: 3- for all aspects above 1800m, weak layers in between
the new snow layers and the wind drift layers are present.

5. snowcover Profil 2 – 23.12. 2515 m, E, 36° (see also overview map)
Snow profile:
Quality of the snowlayering = medium, the Rutschblock does not
fail in the lowest layers Location:
Relatively well prevented from the wind, to some extent representative for the Rinerhorn area. Permafrost leads to a
somehow different snowlayering then elsewhere.
Rutschblock:
The failier was unclear, an lead across all the layers.
Danger signs:
No recent.
Danger:
Moderate, all aspects above 1800m, most dangerous locations
in gullies and bowls with wind drifted snow and transitions from
less to much snow.

6. New snow, water equivalent, 18.12., 8.00 Uhr
new snow 24 h
water equivalent 24 h
new snow 3d
Davos, 1560 m
21 cm
17 mm
89 cm
Weissfluhjoch, 2540 m
29 cm
37 mm
65 cm
Arosa, 1850 m
31 cm
23 mm
82 cm

7. wind, 18.12., 8.00 Uhr Weissfluhjoch, 2693 m mean 43 km/h; speed peak 68 km/h: direction NW

8. temperature
Clear cooling down during the precipitation.

9. avalanche activity
17km
ca. 150km2
17km

10. avalanche activity small: ~130 medium: 29 large: ~1
spontaneous and artificial

11. avalanche activity
Potential for avalanches
reaching the valley floor.

12. avalanche activity – not enumerable in detail
avalanche size 1 2 3 4
spontaneous
little
surcharge
large
area: ca. 150 km²
avalanches in all aspects, above about 1400 m

13. picture 1

14. Bayern Matrix „... numerous little, many medium and few
large avalanches
probable“