At elevated altitudes a considerable avalanche danger will be encountered in some regions
Edition: 18.5.2021, 17:00 / Next update: 19.5.2021, 18:00
Snowpack
Fresh snow and a sometimes strong northwesterly wind will give rise to snow drift accumulations that are prone to triggering on the northern flank of the Alps in particular and in the high Alpine regions in general. In addition, given the low temperatures, any weak layers will stabilise only slowly, so that the fresh snow and snow drift accumulations of recent days will also remain prone to triggering in the high Alpine regions in some cases. In some places, avalanches can release deeper layers of the snowpack. At elevated altitudes, conditions are more wintry than usual at this time of year.
The old snowpack is thoroughly moist below 2500 m on north facing slopes, and up to approximately 3000 m on east, south and west facing slopes. Both wet snow and gliding avalanches remain possible, in particular under the influence of solar radiation.
Observed weather on Tuesday, 18.05.2021
Night-time showers in the north moved away eastwards in the morning. During the day in the south it was mostly sunny, and in the north there was variable cloud with prolonged sunny spells.
Fresh snow
The snowfall level was approximately 1600 m. From Monday afternoon until Tuesday morning, showers gave rise to the following amounts of snow above approximately 2000 m:
  • Extreme west of Lower Valais, northern flank of the Alps, northern Prättigau to Samnaun: 5 to 10 cm
  • Elsewhere: smaller amounts or none
Temperature
At midday at 2000 m: between 0 °C in the north and +7 °C in the far south
Wind
From westerly directions
  • During the night at elevated altitudes, remaining moderate to strong
  • Easing during the day and mostly light in the afternoon
Weather forecast through Wednesday, 19.05.2021
In the north, varying to large amounts of cloud with only brief bright spells and frequent showers will persist, in particular on the northern flank of the Alps. In some instances, thunderstorms are also possible. To the south of the main Alpine ridge it will be mostly sunny in the morning, but convective cloud will build up in the afternoon.
Fresh snow
The snowfall level will be between 1300 and 1600 m. The following amounts of snow will fall above approximately 2000 m in the period from Tuesday until Wednesday afternoon:
  • Northern flank of the Alps: 20 to 40 cm
  • Lower Valais, northern Grisons: 10 to 20 cm
  • Further south: mostly smaller amounts, and south of the main Alpine ridge remaining dry
Temperature
At midday at 2000 m: between -2 °C in the north and +3 °C in the south
Wind
  • In the north, moderate; at elevated altitudes, strong from the northwest, easing a little as the day progresses
  • In the south, moderate to strong northerly in the mountains, with a north foehn reaching down into the valleys in some cases
Outlook through Friday, 21.05.2021
Thursday
In the north it will remain cloudy with some final showers in the morning, before becoming fairly sunny from the west as the day progresses. The south will be sunny with convective cloud in the afternoon. The northwesterly wind will remain mostly moderate, but in the south it will be strong at elevated altitudes. It will ease later and change direction in the evening, becoming southwesterly. The danger of dry avalanches will not change significantly. Solar radiation is expected to give rise to a large number of moist loose snow slides and avalanches in the fresh snow.
Friday
The east will remain bright as a consequence of the foehn wind; otherwise it will be mostly very cloudy. Precipitation will arrive from the west, and the snowfall limit will be approximately 2200 m. The danger of dry avalanches will not change significantly at elevated altitudes. Wet snow avalanche activity will vary slightly during the day.