Avalanche warning for region Hallingdal Tuesday 16.02.2021

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. • Easy to trigger • 2 - Medium • Some steep slopes SE, W above 1300 masl • Flak av RG (blyant) med tykkelse opp mot 30 cm, oppå svakt lag av kantkorn på 3 cm. Underliggende lag av gammel snøfokk. Problemet er bekreftet i SØ og VEST, men det finnes trolig også i andre himmelretninger.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The collapsing weak layer is thin < 3 cm. • Easy to trigger • 1 - Small • Few steep slopes SE, S, SW between 1400 masl and 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 1 - Small • Few steep slopes SE between 1400 masl and 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Some steep slopes S, SW, W above 1300 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • A big and identifiable crystal in the weak layer. • N, NE, NW

• Buried weak layer of surface hoar • Within half a meter • The overlying slab is soft. A big and identifiable crystal in the weak layer.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The collapsing weak layer is thin < 3 cm. The overlying slab is soft. A big and identifiable crystal in the weak layer. • Very easy to trigger • 2 - Medium • Few steep slopes N, NE, E, SE, S, SW, W, NW between 1500 masl and 900 masl • Har blitt observert flere steder. Peoblemet vil øke når flaket oppå blir hardere

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • Easy to trigger • 1 - Small • Some steep slopes E, SE, S, SW, W above unknown masl • - Skredproblemet er på konvekser med tynt snødekke. Det øverste fokklaget er generelt svært hardt og må være tynt for å kunne påvirkes.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • A big and identifiable crystal in the weak layer. • Easy to trigger • 1 - Small • E above 1300 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl • Store variasjoner på dybde og fasthet på overliggende lag.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • 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. • Very easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW between 1400 masl and 900 masl • Me fann overflaterimet under eit mjukt lag av fokksnø. Me klarte dermed ikkje å påverke dette laget men ut i frå andre pitar i området med fokksnø som har flaka seg oppå SH laget var det svært lett å løyse ut flaket og det sklir ut på overflaterimet.

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The weak layer collapses easily and clean (easy propagation). A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW between 1300 masl and 900 masl • Kantkornlaget låg 45 cm under overflata. Dette klarte me å påverke og det sklei ut med ei Q1 verdi. Kantkornlaget Finn me i alle himmelretningar.

Avalanche Problems

• Buried weak layer of surface hoar • Within half a meter • A big and identifiable crystal in the weak layer. • SE, S, SW

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The overlying slab is soft. A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1200 masl

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within a meter • A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • The overlying slab is soft. • Easy to trigger • 2 - Medium • Few steep slopes NE, E, SE above 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within half a meter • The collapsing weak layer is thin < 3 cm. • Very difficult to trigger • 1 - Small • Few steep slopes S between unknown masl and unknown masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • 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. • Very easy to trigger • 2 - Medium • Many steep slopes N, NE, E above unknown masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The overlying slab is soft. • Easy to trigger • 2 - Medium • N, NE, NW above unknown masl • På NORD side av fjellet er laget med nysnø over overflateterimet for mykt til å kunne danne skikkelige flak. På SØR side av fjellet opplevde vi at det var dannet seg et hardt nok flak over overflaterimet til at vi fikk utslag på tester.

Avalanche Problems

• Buried weak layer of surface hoar • Within half a meter • The collapsing weak layer is thin < 3 cm. The overlying slab is soft. A big and identifiable crystal in the weak layer. • W above unknown masl

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 • 2 - Medium • Few steep slopes S, SW, W above 1200 masl • Skredproblemet er mest fremtredende i heng vendt mot SV der vindtransportert snø fra vesentlig areal har lastet inn og blitt til RG-flak på et lag av FC.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • 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. • Very easy to trigger • 2 - Medium • Some steep slopes SW, W, NW above 1300 masl • Laget gikk på RB 2@13cmQ1. Det gled ikke ut, men hellningsvinkel var bare 20 grader.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The overlying slab is soft. A big and identifiable crystal in the weak layer. • Very easy to trigger • 2 - Medium • Few steep slopes N, NE, E, SE, S, SW, W, NW between 1500 masl and 900 masl • Har blitt observert overflaterim flere steder siste dagene. Her er snøen over for myk, men når det kommer mer snø vil risikoen for skred øke.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The overlying slab is soft. A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 900 masl • Finner flere kantkornlag nedover i snødekket, fra forskjellige tidsrom tidligere i vinter, sikkert også stedvis nedføyka rimlag, selv om jeg ikke fant det i dag etter å ha gravd flere steder i forskjellige eksposisjoner. Greit å ha det med i varselet. Mulig at kantkornlag med ugunstige egenskaper, sammen med fokksnøflak, har relativt begrenset utbredelse i terrenget. Men situasjonen er generelt uoversiktlig, og med noen cm ubunden snø på toppen er det vanskelig å identifisere de skumle stedene.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The weak layer collapses easily and clean (easy propagation). A big and identifiable crystal in the weak layer. • Very difficult to trigger • 1 - Small • Some steep slopes N, W, NW above 1200 masl • Funnet i høyder fra 1100-1400

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • 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. • Very easy to trigger • 1 - Small • Some steep slopes N, SW, W, NW above 1500 masl • Observert ned til ca 1200m

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Easy to trigger • 1 - Small • Few steep slopes NE, E, SE between 1300 masl and 1100 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1200 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within a meter • A big and identifiable crystal in the weak layer.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • Easy to trigger • 1 - Small • Some steep slopes N, W, NW above 1100 masl • Påvist problem mellom 1200 til 1400 meter i området Systerskarsfjellet.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • 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 N, NE, E, SE, S, SW, W, NW above 1100 masl

Avalanche Problems

• Buried weak layer of faceted snow near surface • Within half a meter • Difficult to trigger • 1 - Small • S between 1200 masl and 1100 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The collapsing weak layer is thin < 3 cm. The overlying slab is soft. A big and identifiable crystal in the weak layer. • Very easy to trigger • 1 - Small • Few steep slopes SE between 1200 masl and 1100 masl

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). A big and identifiable crystal in the weak layer. • Very easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW between 1500 masl and 1000 masl • Me fann eit vedvarande svakt lag av kantkorn høgt i snødekket. Fokksnøen som låg på toppen var av veldig varrierande hardheit og tjukkelse. Dette kunne me sjå ut i frå andre pitar som blei gravd i området. Nokre stadar ligg FClaget so lågt i snødekket at ein skilaupar ikkje kan påverke det medan andre stader ligg det høgt oppe i snødekket og utgjer eit reelt skredproblem.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • A big and identifiable crystal in the weak layer. • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW between 1500 masl and 900 masl • Vi fikk ikke påvirket det svake laget her, men det er utbredt i området og kan muligens påvirkes enkelte steder.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Very easy to trigger • 1 - Small • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl • Fra 1000-1400 moh er rimkrystallene ca 1-2 cm store. Fra 1400-1600 er rimkrystallene ca 2-3 cm store. Dette gjelder i alle himmelretninger med unntak av sterkt vindutsatte steder. Variere med å ligge i snøoverflaten til ca 5 cm under fokksnøen.

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Some steep slopes NW between 1400 masl and 1000 masl • 5 cm Kantkorn lag i varierende dybde på 20-40 cm, stor variasjon i dybde innenfor små områder.

Avalanche Problems

• Loose dry avalanche • The weak layer collapses easily and clean (easy propagation). • Very easy to trigger • E, SE

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. • Easy to trigger • 1 - Small • Some steep slopes SE, S • Størrelse satt til 1 - Små grunnet nåværende snøfokkmengde, 1-10cm. Merk at resultat og snømengder kun gjelder lokalt på teststedet. Områder med dypere snøfokk og evt fremtidig snøtransport vill øke faren.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • 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. • Very easy to trigger • 1 - Small • Many steep slopes N, NE, E, SE, S, SW, W, NW above 1100 masl • Store rimkrystaller (6-9 mm) som stedvis er sammenfrosset og lett nedføyket (armert) av et slør av nysnø - stedvis nedføyket under fersk fokksnø. Kun utsatte steder vinden har klart å blåse rent for rim. Ved tilførsel av snø og vind vil dette bli spennende i høyden.

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). A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Some steep slopes SW, W above 1100 masl • - observerte harde RG lag over og under det svake kantkornlagt (3-5mm), dette i vindpåvirket områder. - Vi hadde én observasjon i Sørvest som ga drønn og sprekker som skjøt 4-5m. - Vi utelukker ikke dette problemet i utsatte områder i andre himmelretninger.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Easy to trigger • Some steep slopes E, SE above 1100 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Very easy to trigger • 2 - Medium • Some steep slopes N, NE, NW between 1400 masl and 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The weak layer collapses easily and clean (easy propagation). A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Some steep slopes N, W, NW between 1500 masl and 1200 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow above a crust • Within half a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 1 - Small • Some steep slopes N, NE above 1100 masl • Skredproblem er kun gjeldende lokalt N og NØ fra tregrense til en runder toppen (1609 i kartet) i 1500moh og går mot annen himmelretning. Her endres snødekket i stor grad, rim og hardere underliggende snø.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • The collapsing weak layer is thin < 3 cm. A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Few steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • The weak layer collapses easily and clean (easy propagation). The collapsing weak layer is thin < 3 cm. • Very easy to trigger • 1 - Small • Few steep slopes SE, S, SW between 1300 masl and 1000 masl

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Few steep slopes SE, S, SW between 1300 masl and 1000 masl

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • The collapsing weak layer is thin < 3 cm. • Very easy to trigger • 1 - Small • Few steep slopes SE, S, SW between 1200 masl and 1000 masl • Tester ga utslag i øverste snødekket grunnet svakelag under flak.

Avalanche Problems

• Loose snow • Very difficult to trigger • 1 - Small • Few steep slopes N, W, NW between 1400 masl and 1000 masl • Akkurat i den piten eg grov fanst det ikkje noko svakt lag. Men ved 3 andre pitar i området var det eit svakt lag av kankorn under eit flak av fokksnø. Ein kan dermed annta at dette FC laget er utbreidd i fjellområdet, medan akkurat i piten min var snøen prega av hard fokksnø.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • A big and identifiable crystal in the weak layer. • Easy to trigger • 1 - Small • Few steep slopes N, NE, NW above 1300 masl • SH laget var veldig lokalt på få steder under et tynt RG lag. Store deler av heng var nesten bare RG ned til 1 m.

Avalanche Problems

• Dry slab avalanche • The weak layer collapses easily and clean (easy propagation). • Easy to trigger • 1 - Small • Some steep slopes SE between 1500 masl and 1000 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • The collapsing weak layer is thin < 3 cm. • Easy to trigger • 2 - Medium • Some steep slopes E, SE above 1100 masl

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow above a crust • Within half a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 1 - Small • Some steep slopes N, NE above 1100 masl • Skredproblem er kun gjeldende lokalt N og NØ fra tregrense til en runder toppen (1609 i kartet) i 1500moh og går mot annen himmelretning. Her endres snødekket i stor grad, rim og hardere underliggende snø.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of surface hoar • Within half a meter • Difficult to trigger • 1 - Small • Few steep slopes N, NE, NW between unknown masl and unknown masl • Det svake laget er blitt nedføyket av 1 cm DF

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within half a meter • A big and identifiable crystal in the weak layer. • Very difficult to trigger • 1 - Small • N, NE, NW above unknown masl

Avalanche Problems

• Buried weak layer of faceted snow near surface • Within a meter • Some steep slopes N, NE, E, SE, S, SW, W, NW between 1300 masl and 900 masl • Kantkornlaget trenger stor tilleggsbelastning. Kan være ett problem der snømassen over er tynnere

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near surface • Within half a meter • A big and identifiable crystal in the weak layer. • Very difficult to trigger • 1 - Small • Some steep slopes N, NE, NW between 1200 masl and 1000 masl • Vedvarende svakt lag ligger i toppen av snødekket, laget av kantkorn er 30 cm tykt og utgjør pr nå ikke en stor risiko. Mer snø oppå dette igjen vil kunne øke skredfaren.