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  INSTITUTE FOR SNOW AND AVALANCHE RESEARCH  DAVOS
               NATIONAL AVALANCHE BULLETIN NO. 78
           from Tuesday, 13 February 2007, 18:30 hours
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  WIDESPREAD CONSIDERABLE AVALANCHE DANGER
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CURRENT CONDITIONS

On Monday night a lot of snow fell in the west. During the day 
snow fell mainly on the northern flanks of the Alps and in the 
northern regions of Grisons. In the south it was generally 
sunny. The moderate to strong wind was gusty; its direction 
changed from westerly to north-westerly. Midday temperatures at 
2000 m were about minus 5 degrees in the north and minus 2 
degrees in the south. 
Since Saturday morning the following amounts of snow have fallen 
above approximately 1800 m: Le Trient region up to 120 cm; Vaud 
and Fribourg Alps, Lower Valais and northern Valais 50 to 80 cm; 
rest of Valais, remaining northern flanks of the Alps and 
northern regions of Grisons 30 to 50 cm, elsewhere 10 to 20 cm. 
In central and southern Ticino the weather was dry. 
Large snow drift accumulations have formed in Valais and on the 
northern flanks of the Alps. The layers of fresh and older wind-
deposited snow are still poorly bonded.


SHORT-TERM DEVELOPMENT

A few more centimetres of snow will fall in the north-east of 
the Swiss Alps by Wednesday morning. The weather will then 
become calmer here as well. During the day fresh cloud will 
build up from the west and light snow will fall. Midday 
temperatures at 2000 m will rise to plus 2 degrees in the north. 
In the south they will remain at about minus 2 degrees. The wind 
direction will change to south-westerly. The wind will remain 
moderate to strong. 
Further generally small snow drift accumulations continue to 
form. The snow pack will settle, especially in the areas exposed 
to heavier snowfall. The avalanche situation for those engaging 
in winter sports remains nonetheless difficult.


AVALANCHE DANGER FORECAST FOR WEDNESDAY

Northern flanks of the Alps; Valais; Gotthard region; Northern 
and Central Grisons; Engadine, Bernina Pass and Ofen Pass:
  Considerable avalanche danger (level 3)
The avalanche prone locations are, in particular, wind-loaded 
slopes of all aspects. They are above approximately 1800 m on 
the northern flanks of the Alps and above approximately 2000 
m elsewhere. The likelihood of avalanche triggering is high. 
Isolated natural avalanches can still occur. In the west in 
particular these can be medium-sized avalanches. Caution and 
extensive experience in the assessment of avalanche danger 
are required.

Remaining areas of the Swiss Alps:
  Moderate avalanche danger (level 2)
Avalanche prone locations are to be found, in particular, in 
gullies and bowls of all aspects above approximately 2200 m.

Especially in the west and north, small wet snow slides can 
occur below approximately 1800 m.


TREND FOR THURSDAY AND FRIDAY

On Wednesday night a little snow will fall in the north. It will 
then remain sunny until Friday. The temperature in the mountains 
will fall on Thursday, but on Friday a foehn wind will give rise 
to very mild weather. The danger of dry avalanches will decrease 
slowly. On Friday an increasing number of small wet snow slides 
and avalanches can be expected.