As a consequence of new snow and wind a considerable avalanche danger will be encountered over a wide area
Edition: 4.5.2021, 17:00 / Next update: 5.5.2021, 18:00
Snowpack
On Monday numerous shallow, but sometimes expansive avalanches were released in the high Alpine regions. In most cases, the gliding masses consisted of last week’s fresh snow and snow drift accumulations. On Tuesday the wind transported a little loosely bonded old snow, in particular on steep shady slopes at high altitudes and generally in the high Alpine regions.
Underneath last week’s fresh snow and snow drift accumulations, the old snow is thoroughly moist on east, south and west facing slopes below approximately 3000 m. On north facing slopes between 2200 and 2500 m, in recent days it has become moist all the way through for the first time, and thus weakened. As a consequence of cool and dull weather, moisture will not penetrate the snowpack any further on Wednesday.
Observed weather on Tuesday, 04.05.2021
The night was overcast in the south, but otherwise clear. Tuesday morning was partly sunny despite high-altitude cloud, but then it became increasingly cloudy. There were isolated bright spells in the south.
Fresh snow
-
Temperature
At midday at 2000 m: about +2 °C
Wind
Moderate to strong southwesterly
Weather forecast through Wednesday, 05.05.2021
It will be very cloudy and windy, and snow will fall down to intermediate altitudes. In the far west the snowfall will be heavy. In the west there will be bright spells in the afternoon. In the south the northerly wind will pick up and it will become mostly sunny as the day progresses.
Fresh snow
The snowfall level will drop from 1800 to 1200 m. In the period until the precipitation ceases on Wednesday evening, the following amounts of snow will fall:
  • Extreme west of Lower Valais: 30 to 50 cm
  • Rest of the northern flank of the Alps, northern Valais, rest of western Lower Valais: 15 to 25 cm; locally more in the Vaud and Fribourg Alps
  • Elsewhere: 5 to 15 cm over a wide area; dry in the far south
Temperature
At midday at 2000 m: between -4 °C in the north and +2 °C in the south
Wind
Strong and even storm force in some localities:
  • During the night from the west to southwest
  • During the day from the west to northwest, and a developing foehn wind in the south
Outlook through Friday, 07.05.2021
Thursday
In the east and south there will be further sunny spells in the morning, otherwise it will be very cloudy. In the afternoon in the west, heavy precipitation will commence and the snowfall level will quickly rise to approximately 2000 m. In the mountains there will be a strong southwesterly wind.
The avalanche danger will decrease a little. In the far west it will increase again in the afternoon.
Friday
It will be very cloudy with precipitation. 20 to 40 cm of fresh snow is expected in the west and north, and approximately 60 cm in the extreme west of Lower Valais. The snowfall level will drop gradually to approximately 1500 m. The wind will remain frequently strong from the west to northwest. The south will be quite sunny during the day with a northerly wind.
The avalanche danger will increase significantly in the north and west. In the extreme west of Lower Valais, danger level 4 (high) may be reached. In the south and in Grisons, the avalanche danger will not change significantly.