Avalanche forecast for Vest-Telemark Sunday 2018-01-21

3
Considerable
Published:

Updated evening Jan 20th!:Demanding conditions with several avalanche problems. Be especilally careful in areas where persistant weak layers can be hidden beneath fresh wind deposited snow.

Persistent slab avalanches

Buried weak layer of faceted snow above a crust

Avoid skiing in steep terrain (more than 30 degrees) and in runout zones. NB, remote triggering is likely. Make very conservative route choices, especially in unknown terrain, after snowfall and if temperatures rise. Identifying areas where the weak layer is present might be difficult and requires experience. Danger signs are whoumpf-sounds, cracking and recent avalanches. However, absence of signs does not mean it is safe.
Slab avalanche
3 - Medium
High additional load
Some steep slopes
Possible

Persistent slab avalanches

Buried weak layer of surface hoar

Avoid skiing in steep terrain (more than 30 degrees) and in runout zones. NB, remote triggering is likely. Make very conservative route choices, especially in unknown terrain, after snowfall and if temperatures rise. Identifying areas where the weak layer is present might be difficult and requires experience. Danger signs are whoumpf-sounds, cracking and recent avalanches. However, absence of signs does not mean it is safe.
Slab avalanche
2 - Small
Low additional load
Some steep slopes
Possible

Wind slab avalanches

Buried weak layer of new snow

Avoid steep (more than 30 degrees) areas with fresh wind deposited snow, especially convex terrain. An avalanche is easier to trigger where wind slabs are thin or soft. Look for areas where the wind recently has deposited snow, typically behind ridges, ribs and in gullies. Remember that local wind effects will cause variation in where the wind slabs occur.
Slab avalanche
2 - Small
Low additional load
Some steep slopes
Possible

What are avalanche problems?

Rainfall
6 mm to 12 mm in the most exposed areas
Wind
Breeze from southeast
Temperature
-12 °C til -9 °C på 1400 moh
Cloud cover
Cloudy

For updated info, please visit yr.no
Rainfall
0 mm
Wind
Breeze from south
Temperature
-18 °C til -10 °C på 1400 moh
Cloud cover
Partly cloudy

For updated info, please visit yr.no

The bulletin does not include a detailed text about the avalanche conditions. This is only given in Norwegian. Translate it using google translate if you like. The text result will be informative, and most likely amusing

For planning your trip and recognizing avalanche terrain, use maps.

Norway has 1:50 000 maps for the whole country. Maps can be bought at bookstores and sports shops, or printed from the net.

Visit www.ut.no for topographic maps online. For slope angle maps, see NGI slope angel maps ("helning" means slope angle).

Modelled snowpack and historic and current weather information can be found on the webpage senorge.no. This site uses information from the weather stations and interpolate values from the stations for gridded maps.

Detailed weather forecast can be found online at www.yr.no or www.storm.no. Yr.no is also in English, but the weather in text format is only given in Norwegian.