24.12.2005 case history 20.-23.12. temperature rise and settlement of snowcover, increasing snowpack stability level 3 2 16.-18.12. heavy snowfall level 4 23.12. snowfall (10-20 cm), light rain in low altitudes, clear up during the night to 24.12. Danger level 2 1 2 mäßig Die Schneedecke ist an einigen Steilhängen *) nur mäßig verfestigt, ansonsten allgemein gut verfestigt. Auslösung ist insbesondere bei großer Zusatzbelastung **) vor allem an den angegebenen Steilhängen möglich. Große spontane Lawinen sind nicht zu erwarten. moderate The snowpack is moderately well bonded on some steep slopes * otherwise generally well bonded. Triggering possible with high additional loads ** , particularly on the steep slopes indicated in the bulletin. Large natural avalanches not likely. 3 4 5 4 3 2 4 4 3 2 2 2
Transcript
24.12.2005case history
20.-23.12. temperature rise and settlement of snowcover, increasing snowpack stability level 3 2
16.-18.12. heavy snowfall level 4
23.12. snowfall (10-20 cm), light rain in low altitudes,clear up during the night to 24.12.
Danger level 2
1
2 mäßig
Die Schneedecke ist an einigen Steilhängen *) nur mäßig verfestigt, ansonsten allgemein gut verfestigt.
Auslösung ist insbesondere bei großer Zusatzbelastung **) vor allem an den angegebenen Steilhängen möglich. Große spontane Lawinen sind nicht zu erwarten.
moderate
The snowpack is moderately well bonded on some steep slopes * otherwise generally well bonded.
Triggering possible with high additional loads ** , particularly on the steep slopes indicated in the bulletin. Large natural avalanches not likely.
3
4
5
4 3 24 4 3 22 2
case history
20.-23.12. temperature rise and settlement of snowcover, increasing snowpack stability level 3 2
16.-18.12. heavy snowfall level 4
23.12. snowfall (10-20 cm), light rain in low altitudes,clear up during the night to 24.12.
visible weak layer between 50 and 80cm beneath the surface• the weak layer breaks plain, but not until high additional loading• the weak layer is relatively thin• the overlaying layers are bonded and rather compact
Analysis of the weak layers: (on a basis of several snow profiles and stabiliy tests):
good bonding between the new snow and the old snow cover surface (by reason of temperature and particular rain
Danger level 2
locations, where avalanches can come up ?
slopes near the ridge line and gullies with wind drifted snow frequency: some slopes,
locations definable,
spontaneous avalanches ?
only little avalanches, due to warming snow surface,
Release probability ?
a single skier is in general not enough
additional load, large additional load
necessary,
Danger level 2
Avalanche report for the Bavarian AlpsSaturday, 24.12.2005, 07.30 am
General:- 10 to 20cm new snow during the last 24 hours, light rain in low altitudes- clear up during the night.- Today: sonny by changing cloudy conditions, temperatures rising up to zero degrees at 2000 m
Snowcover conditions:Low altidudes:- slightly moist snowsurface as a result of the rain- thin melt-freeze crust as a result of the clearence during the night, up to intermediate altitudes- In intermediate elevations the new snow lies on a well settled old snow cover that is still powdery.- good bonding between the new snow and the old snow cover surface
Above the tree line:- from the wind intensely affected snowcover- Keep in mind the week bonding between the intens faceted snow layers near the ground and the overlaying wind packed layers.- Yesterday during the day little, fresh snow drinft accumulations were built up temporary by northwesterly winds.
Avalanche danger:- moderate avalanche danger- avalanche prone terrain: mainly steep terrain adjacent to the ridge line in the aspects N-E-SE above about 1800m as well as in gullies and bowls with snow drift accumulations- Mainly in transition zones between bear areas and slopes charged with wind drift acculuations in particular with high additional loading, e.g. a goup without spacing, the release of a slab avalanche is possible.- As a result of the warming during the day and the insolation the new snow of the last days may release as little, superficial loose snow avalanches and slab avalanches on rocky, steep slopes.- In low and intermediate altitudes ground avalanches may occur as a result of the increasing humidity penetration.
Danger level 2
Information from observers, avalanches
No avalanche releases in high altitudes. Few little wet snow avalanches near the snow surface (loose snow avalanches) in SE-S-SW exposed slopes between 1300 and 1800m.
Few little loose snow and full-depth slab avalanches in SE-S-.SW exposed slopes below 1300m.
Information from observers, avalanches
No avalanche releases in high altitudes. Few little wet snow avalanches near the snow surface (loose snow avalanches) in SE-S-SW exposed slopes between 1300 and 1800m.
Few little loose snow and full-depth slab avalanches in SE-S-.SW exposed slopes below 1300m.
