Considerable avalanche danger due to heavy snowfall in places

 In a nutshell...

A cold front is delivering fresh snow down to intermediate altitudes. At elevated altitudes conditions for a short time will be like in deep winter. Simultaneously, avalanche danger in many places has increased to considerable. We expect higher likelihood of slab avalanches getting triggered by winter sports enthusiasts, and also increasingly frequent natural triggerings.

Fresh snow plus wind:  ratcheting up avalanche danger

Currently (13.04.2023) it is snowing in far-reaching parts of Tirol. Up to now there has been up to 40 cm of fresh snow registered from place to place, most in the western and eastern regions of North Tirol, also in southern and furthermost northern East Tirol.

Map by Hydro Online shows overall 48-hr snowfall (time: 4:00 pm on 13.04.2023)

48-hr fresh snow forecast 13.04.-14.04.2023

Precipitation / wind forecast for a heavy-precipitation region. Winds will intensify tomorrow, Friday, 14.04.

Slab avalanches, loose-snow avalanches, glide-snow avalanches

Lots of fresh snowfall in late spring always means that increased avalanche activity can be expected, at latest, as of the first bright intervals, in other words, when diffuse radiation begins. These will be primarily loose-snow avalanches in extremely steep terrain. In the regions where snowfall has been heaviest they can be of medium size. Besides that, heightened likelihood of slab avalanches can also be expected. Slab avalanches can currently be unleashed by several different causes:

• The winds (expected to intensify tomorrow, 14.04) transports the fresh snow, generates fresh snowdrift accumulations. The frequency and proneness to triggering of fresh drifts increase with ascending altitude.
• In regions where precipitation is heavy but winds are light, near-surface loose snow can be bonded by diffuse radiation. Thereby, a slab forms near the surface. The still loose, cold snow beneath it serves as the necessary weak layer for the slab, active for a brief spell.
• In regions where snowfall has been especially heavy, slab avalanches can break through the snowpack in isolated cases, likeliest at mid-level. This will occur most frequently above 2600m. (Weak layer due to cold on warm, see  Blog. Fractures down to ground level can’t be ruled out.

This photo dating from 06.04.2023 shows a large-sized avalanche on an extremely steep E/NE facing slope at about 3000m in the Kühtai-Geigenkamm region. In regions where snowfall has been heaviest, similar naturally triggered avalanches are possible in isolated cases.

In addition, glide-snow slides and glide-snow avalanches will also be observed, particularly in regions where snowfall has been heaviest. This is most likely to occur on steep, grass-covered slopes where prior to this bout of precipitation the ground was bare.

For a short time: treacherous conditions. Then a rapidly improving situation in view. Thereafter, future developments still uncertain.

We assume a highly treacherous situation for winter sports enthusiasts for a brief spell. In southern East Tirol where weather conditions will improve more swiftly, the fact is that on the first day of fine weather (even if only a short spell of it) the risks in backcountry are especially high. It is also characteristic of the season that the near-surface snowpack rapidly improves and stabilizes. Due to April weather caprices, we still need to await coming conditions before we say anything more.