Avalanche warning for region Hallingdal Wednesday 18.12.2019

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • The overlying slab is soft. A big and identifiable crystal in the weak layer. • Store lokale forskjeller, små flak

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • The collapsing weak layer is thin < 3 cm. The overlying slab is soft. • Difficult to trigger • N, NE, E, SE, S, SW, W, NW between unknown masl and unknown masl • Problemet ligger spredt i mange himmelretninger men utgjør bare små, tynne lokale flak

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • The overlying slab is soft. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S above 1000 masl • Ferskest fokksnø i Ø-vendte heng. Virker forholdsvis stabilt. Litt tørr nysnø på toppen gjør det vanskelig å lese hvor skredproblemet er mest aktivt

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Few steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl • Kantkornlag fins enten ved bakken eller rundt mer og mindre oppbrutte skarelag, mest framtredende der snødekket er tynt ved rabber og rygger. Liten utbredelse som skredproblem

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • The overlying slab is soft. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE above 1000 masl • Staniliseres relativt raskt og krever mer tb, men skredproblem er akutt nå.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. The overlying slab is soft. A big and identifiable crystal in the weak layer. • Easy to trigger • 1 - Small • Few steep slopes E, SE, S above 1300 masl • Lett identifiserbart skredproblem. finnes i leområder uavhengig av himmelretning, men trolig mest Ø-S sektor.

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Some steep slopes • det svake laget finnes i alle himmelretninger, men det er ikke overalt det er nok snø over. Trolig størst problem rundt skoggrensa, over dette blir overliggende snø svært hard.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Very difficult to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 800 masl • Dette svake laget kan finnes under 800 moh, observasjon er ikke utført under denne høyden.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Very difficult to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 800 masl • Ingen observasjon gjort under 800moh, kan ikke utelukke at skredproblem går lavere.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. The overlying slab is soft. A big and identifiable crystal in the weak layer. • Easy to trigger • 1 - Small • Some steep slopes between unknown masl and unknown masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within half a meter • Very difficult to trigger • 2 - Medium • Some steep slopes N, NE, W, NW above 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within half a meter • Very difficult to trigger • 2 - Medium • Some steep slopes N, NE, W, NW above 1000 masl

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • Very difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 900 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Very difficult to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 800 masl • Obstur startet på 800moh (ingen obs fra lavere i dalen)

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Very difficult to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 800 masl • Utelukker ikke at problemet er til stede på lavere høyde, men har ikke observert lavere enn 800moh.

Avalanche Problems

• Dry slab avalanche • Difficult to trigger • 1 - Small • Few steep slopes N, NE, NW between 1300 masl and 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • The overlying slab is soft. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, W, NW above 1100 masl • Som en følge av vind og nedbør fra s og sø.

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Few steep slopes N, NE, E, SE, S, SW, W, NW above 1100 masl • Kantkornlag ved bakken finnes overalt i terrenget, men mine observasjoner den siste perioden tilsier at problemet bare er reelt noen få steder. Det er der den aller første snøen som kom i år la seg til, i forsenkninger og lune formasjoner. Denne første snøen har dannet et smelt/frys lag som kantkornet snø har lagt seg over. Der denne kombinasjonen av faktorer finnes kan man oppleve å skape brudd og få forplantning I dette svake laget. Skredstr vil etter min oppfatning bli begrenset til str 2, da områdene som skaper forutsetning for skred i dette laget har begrenset utstrekning.