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  INSTITUTE FOR SNOW AND AVALANCHE RESEARCH  DAVOS
               NATIONAL AVALANCHE BULLETIN NO. 80
           from Thursday, 15 February 2007, 18:30 hours
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  REGIONALLY CONSIDERABLE AVALANCHE DANGER
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CURRENT CONDITIONS

By Thursday midday in Lower Valais, on the northern flanks of 
the Alps and in northern Grisons, 5 to 20 cm of snow fell. The 
snow line in the west was initially at about 1800 m, then sank 
lower. In the morning, clouds moved past the eastern part of the 
northern flanks of the Alps. Subsequently it became 
predominantly sunny in the west, as it already was in the 
remaining regions. Moderate to strong winds shifted towards 
north to northeast and prevailed throughout the day. Midday 
temperatures at 2000 m were minus 4 degrees in the north and 
plus 2 degrees in the south. 
The snowdrift accumulations of recent days are large, 
particularly in the west. The bonding between the various 
snowdrift layers is partly still weak.


SHORT-TERM DEVELOPMENT

On Friday it will be sunny. Midday temperatures at 2000 m will 
increase markedly. In the west and the south the temperature 
will be plus 6 degrees and in the east, plus 1 degree. Light to 
moderate northeasterly winds will prevail. 
The snowpack will continue to settle. With the intense warming 
the likelihood of dry avalanches being released will increase 
temporarily. On sunny slopes, the snowpack will become moist 
well into higher altitude zones.


AVALANCHE DANGER FORECAST FOR FRIDAY

Northern Alpine ridge; Leysin; Pays d'Enhaut; Gstaad; Lenk; 
Valais, Gotthard region; northern and central Grisons not 
including Zervreila, Rheinwald and Avers; Engadine and 
Ofenpass:
  Considerable Avalanche Danger (Level 3)
On the northern Alpine ridge from the Glarus Alps to 
Liechtenstein as well as in the indicated areas of Grisons, 
the avalanche prone locations are primarily in gullies, bowls 
and areas adjacent to the ridge line in all aspects above 
approximately 2200 m. 
In the remaining regions of this danger level, the avalanche 
prone locations are more widely spread. They are primarily on 
snowdrift slopes in all aspects above approximately 2000 m. 
Single persons can trigger avalanches. In the west these can 
attain medium size. Extensive experience in the assessment of 
avalanche danger and maintaining distances between persons 
are important.

The remaining regions of the Swiss Alps:
  Moderate Avalanche Danger (Level 2)
In the northern regions of this danger level, the avalanche 
prone locations are on snowdrift slopes in all aspects above 
approximately 1800 m in particular. In the southern regions 
of this danger level, avalanche prone locations are primarily 
in gullies and bowls in all aspects above approximately 2200 
m.

Due to the warming and the radiation, moist snow slides and 
avalanches can be expected. On sunny slopes, they should be 
anticipated below about 2800 m, otherwise below about 2000 m.


TREND FOR SATURDAY AND SUNDAY

On Saturday in the north it will be sunny and in the south 
overcast. On Sunday in the east it will be sunny, elsewhere 
cloudy. Temperatures will decrease. The avalanche danger will 
diminish.