Snow conditions 10.12.2021

General danger level - Friday, 10 December 2021
Danger is level 3 on the European 5-level scale - CONSIDERABLE.
Main problem: new snow, wind slab
Danger pattern: Cold weather, poorly bonded fresh snow with wind

Risk assessment
Avalanche danger is mainly above the treeline CONSIDERABLE, level 3, lower down mostly MODERATE, level 2. Particularly dangerous are steep slopes where numerous small and occasional medium-sized avalanches of dry, poorly bonded snow can release, as well as wind slab areas, which due to changeable wind direction are on all aspects. Snow has also covered old crusts, so the danger is hard to recognise. Especially where there is less new snow, you can trigger a slab avalanche under minor loading.

Snow conditions
Until Thursday morning, 20 to 50 cm of snow fell in the mountains, mainly depending on altitude. Above around 1200 m the snow was dry throughout, lower down it was initially wet in places. The new snow is mostly soft and light. On wind-exposed sites it is quite drifted, sometimes down to the old base which is crusted or hard. There is a lot of wind slab, and a crust may have formed due to the wind in places. Locally weak layers exist under the layer of new snow. These are mainly where there was previously a crust. This formed in the mid-mountains due to thawing and freezing, higher up mainly due to wind. Movement is quite difficult due to the large amount of snow.

Forecast weather development
Today it will be moderately cloudy at times, occasionally mostly cloudy. Initially, hills will be in clouds in places, which will dry out during the day. A weak wind will blow, moderate westerly or south-westerly in the high mountains. Temperatures will be below zero. Tomorrow it will be mostly clear and cold. A weak to moderate northerly wind will blow, strengthening in the high mountains towards evening. On Sunday it will be mostly clear and quite windy. A strong northerly wind will blow. The zero isotherm will rise to around 1100 m above sea level in the afternoon. Dry weather will continue into the beginning of next week. It will be somewhat warmer, the freezing level will be around 1800 m above sea level on Monday, then a little higher.

Trend in snow conditions
Due to low temperatures, the snow in the hills and mountains will remain dry, soft and poorly bonded by the end of the week. Today the westerly wind will transport snow on wind-exposed sites, but mainly tomorrow and even more on Sunday the northerly wind, which will be stronger, will completely blow away the new snow in many places and numerous new slabs will form on south-facing slopes and sides of ridges and saddles. Overall, the avalanche danger will not increase significantly, but it will be HARD TO RECOGNISE and POTENTIALLY LARGE. Mainly steep and moderately steep slopes with wind slab will be dangerous, where you can trigger a slab avalanche with just minor loading. Dry, poorly bonded snow avalanches may still release from steep slopes. There will be a risk of slipping on ridges. When going into the mountains, choose avalanche-safer terrain. EVEN FULL EQUIPMENT WILL NOT PROTECT YOU FROM AN AVALANCHE if you do not choose safe routes on your way.

Next issue: Monday, 13 December 2021

Source: ARSO