Wintery in the mountains again

One of the driest months of March in history is behind us. And now, winter is coming back.

With the precipitation beginning today, 31.03, the not-quite-driest month of March in measurement history comes to an end. For Innsbruck, however, it was the sunniest March in measurement history. That is now at an end. April with its well known variable character seems to be arriving right on schedule. In Tirol, precipitation will set in everywhere today, initially as rainfall at intermediate altitudes, successively over the next few days as snowfall down to the valley floor. In the mountains, up to 50 cm of fresh snow is anticipated by Sunday, 03.04, more from place to place. The southerly/southwesterly air current will shift to a northerly air current. Winds will tend to be light. Weather conditions remind us of situations which are typical of springtime: due to increasing convective precipitation, highly varied snow depths can be expected, but also quite pronounced increases in fresh snow depths with ascending altitude.

72hr-fresh snow totals until Sunday, 03.04.2022

End of the dry period: on 30.03 in southern East Tirol, precipitation set in.
Temperatures dropping significantly.

Avalanche danger is increasing (somewhat), after a long phase of favorable conditions

During the month of March, a short interim of favorable condition, frequently with low avalanche danger, prevailed (mid-March had a pronounced springtime avalanche cycle).

Prior to snowfall we always intensely analyse the layering of the old snowpack and the old snowpack surface. Both have immediate impact on future avalanche danger. Currently, the point of departure is good: the old snowpack is stable throughout Tirol, the old snowpack surface is irregularly configured.

Snowpack analysis together with avalanche dogs in Kühtai, northern Stubai Alps.
(photo: 29.03.2022)

 

Irregularly configured old snowpack surface. Silvretta. (photo: 25.03.2022)

Unusually raw and irregular: ragged snow on very steep, sunny slopes. Liebenerspitze, Ötztal Alps. (photo: 26.03.2022)

Due to these conditions as a point of departure, but also due to light winds during the previous rounds of snowfall, avalanche danger will increase only slowly. Problem zones still have to evolve inside the masses of fresh snow. The following scenarios are imaginable:

• In the zones where fresh snowfall is heaviest and where winds are strong enough for snow transport, fresh snowdrift accumulations will be generated. A weak layer is possible to begin with beneath the snow which fell without much wind impact. Caution urged on very steep, wind-protected, ridgeline slopes.
• Loose-snow avalanches on extremely steep slopes: these will be observed with increasing frequency whenever the sun comes out in wind-protected zones where snowfall is heavy. This will probably be next Monday, 04.04.
• Slab avalanches in areas where snowfall is heaviest and winds are light will occur whenever the sun comes out. Due to solar radiation the snowpack will be well consolidated, and thereby, a slab can form. The weak layer is the layer of still loose powder snow beneath it. This will be a short-lived problem which, however, can expand rather quickly, especially amid diffuse light conditions.
• Glide-snow avalanches: these can release in very isolated cases on steep, smooth slopes near the already existing glide cracks in the snowpack. Also conceivable, in addition, are relatively small glide-snow avalanches on steep grass-covered slopes in the zones where fresh snowfall is heaviest where the slopes were already bare before the precipitation.
  

Cracks in the snowpack: bellwethers of gliding movement of the snowpack. Griesner Alm - Wilder Kaiser (photo: 28.03.2022)

Encircled: potential glide-snow problem. Gamskopf, western Kitzbühel Alps (photo: 27.03.2022)

Unusual: below average snow depths

Startlingly visible at our long-term observation stations: there is too little snow for this juncture of the season. In some places we are nearing the minimum of snow measured thus far, over a period of 60 years.

Upper graph: snow depth maximum and minimum and average until now, including current overall snow depths in winter 2021-22. Lower graph: red bars show fresh snow. 

Extreme dryness in sunny terrain. Venediger Massif. (photo: 28.03.2022)

View from Kraspespitze, northern Stubai Alps, towards the north. (photo: 27.03.2022)

Ski piste in the lowlands of North Tirol (photo: 28.03.2022)