Avalanche warning for region Hallingdal Thursday 12.12.2019

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. • Easy to trigger • 1 - Small • Some steep slopes N, W, NW • Mer utsatt i høyden hvor vinden har blitt transportert. Har kun fått vurdert snøen over 1000moh

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • 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

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, W, NW above 900 masl

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • 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 • Many steep slopes N, NE, W, NW above 1000 masl • Må ha vindtransportert snø i overliggende lag for å danne flakskred, dette finner vi hovedsaklig i leområder.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • The collapsing weak layer is thin < 3 cm. • Easy to trigger • 1 - Small • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl

Avalanche Problems

• Dry slab avalanche • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • 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, W, NW above 1100 masl • Finn skredproblemet i noen renner, bak rygger i nord og nordøst, nordvest. Lettest å utløse der snødekekt er tynt.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within 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, W, NW above 1000 masl • Utbredt kantkornlag ved bakken, men trenger stor tilleggsbelastning for å påvirkes.

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. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, W, NW above 1100 masl • Det svaje laget finnes nok i alle himmelretninger, men er i nordlig sektor det er flak over.

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. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, SE, S, SW, W, NW above 1100 masl • Det svake laget finnes i alle himmelretninger, men skredproblemet er kun der det finnes flak av fokksnø. Vi har ikke vært høyere enn 1100 moh i dag, og har begrenset informasjon om hva som har skjedd i høyden siste døgn. Antar at dette er likt som i går. Vi beveget oss nedover fra Harahorn og finner kantkornlaget ved 1000moh, men laget virker helt dødt - ingen resultater på LBT.

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. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, W, NW above 1000 masl

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • 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 • Many steep slopes N, NE, W, NW above 1000 masl

Avalanche Problems

• Buried weak layer of new snow • Some steep slopes NE, W, NW above 1000 masl

• Buried weak layer of faceted snow beneath a crust • Within half a meter • The collapsing weak layer is thin < 3 cm.

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. • Difficult to trigger • 1 - Small • Some steep slopes N, NE, E, W, NW above 1000 masl

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • 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, W, NW 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. 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 1100 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. • Easy to trigger • 2 - Medium • Few steep slopes N, NE, E, W, NW above 1200 masl • Finner kantkorn og beger ved bakken over alt hvor vi har gått. Man kan klare å påvirke det steder der snødekket er tynt og har ett hardt lag over seg, typisk nære nabber og rygger.

• Dry slab avalanche • Buried weak layer of new snow • Within half a meter • A big and identifiable crystal in the weak layer. • Difficult to trigger • 1 - Small • Few steep slopes N, NE, E, SE, S, SW, W, NW above 1200 masl • Noen steder finner vi ett lag med nedføyket myk løssnø. Det er veldig varierende snødekket. Vi gjorde LBT i alle himmel rettinger, alle brudd i Q3 etter mange slag. Vi har kun bevegd oss over 1200moh.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow above a crust • Within half a meter • The collapsing weak layer is thin < 3 cm. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, NW below 1200 masl • Skarelag observert opp mot 1250 moh. igår i nærområdet. Flaket over er fokksnø som er blåst inn frå S-SA.

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. • Difficult to trigger • 2 - Medium • Few steep slopes N, NE, NW above 2500 masl • Svakt lag finnes trolig generelt og i flere himmelretninger, men fokksnø (flak) er i hovedsak avsatt i nordvendte heng (NW-N-NE).

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within a meter • The weak layer collapses easily and clean (easy propagation). A big and identifiable crystal in the weak layer. • Easy to trigger • 1 - Small • Few steep slopes N, NE, NW above unknown masl

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within a meter • The collapsing weak layer is thin < 3 cm. • Easy to trigger • 1 - Small • Few steep slopes N, NE, NW above 2500 masl • Mulig problem i leheng med vindtransportert pålagret snø.

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. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, W, NW above 1000 masl • 10 cm lag fra bakken med kantkorn ca 2 - 2,5 mm. Vanskelig å løse ut

• 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 • 2 - Medium • N, NE, E, W, NW above 1000 masl • Meget tynt skarelag. Pakket fokksnø over og under.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within 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, W, NW above 1100 masl • The faceting was widespread, but the overlying load was variable due to spatial variability in the terrain and loading of the storm slab.

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, W, NW above 1000 masl • Vind fra SØ sist natt med samtidig snøfall. Pålagring vil trolig ha skjedd i le retning av vinden.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within half a meter • A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Few steep slopes N, NE, E, W, NW above 1200 masl • Hard fokksnø nokon plassar, men mjukare innimellom. Me kan ikkje seie om skredproblemet går heilt til topps. Me gjekk hardt ut for å finne skredproblematikk i fokksnøen, men dette fant me ikkje. Over tregrensa har det vore mykje vind inatt og snøen er blåst inn i lesider og i forsenkningar i terrenget.

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. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, E, W, NW above 1000 masl • Nødvendig med vindtransportert snø i leområder for å løse ut flakskred. Det er fokksnø over tregrensa og i aspektet V til N til Ø. Det er også registrert svake lag i fokksnø og svakt lag ved skare, det er lett å løse ut, men tilstede i få heng.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within 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, W, NW above 1000 masl • Kantkornlag er utbredt, men ikke veldig potent og krever stor tilleggsbelastning for å trigges.

Avalanche Problems

• Dry slab avalanche • A big and identifiable crystal in the weak layer. • Difficult to trigger • 2 - Medium • Few steep slopes N, NW

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • The overlying slab is soft. A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl • Kant korn ved bakken, kantkorn er best utviklet hvor snødekke er tynt.

• Poor bonding between layers in wind deposited snow • Easy to trigger • 1 - Small • Some steep slopes N, NE, E above 1000 masl • Mye vind transport i høyden. Kan være dårlig binding i fokk snøen i noen heng

• Buried weak layer of faceted snow beneath a crust • Easy to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 1000 masl • Oppbyggende utvikling ved skare lag i snødekket. Bør følge med dette laget

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within half a meter • 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 1200 masl • Hard fokksnø noen plasser, noe mykt innimellom. Vi kan ikke si noe om snøproblemet går helt til topps. Vi lette etter skredproblem i fokksnøen, dette fant vi ikke. Vi hadde en del drønn i snøen, der vi påvirket kantkornlaget nederst i snødekket. Der snødekket er tynt påvirket vi snødekket lett.

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. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, W, NW above 800 masl • Veldig usikker på hvor langt ned dette problemet går, vi har ikke vært lavere enn 1100moh, og skredproblemet var tilstede her. Vi har kun vært i nordlig sektor, kan ikke si noe om utbredelsen utover dette, men forventer at problemet er tilstede alle steder der det ligger et flak.

• Dry slab avalanche • Buried weak layer of faceted snow beneath a crust • Within half a meter • The collapsing weak layer is thin < 3 cm. The overlying slab is soft. • Difficult to trigger • 2 - Medium • Few steep slopes N, NE, E, W, NW not between 1300 masl and 800 masl • Dette skredproblemet er mindre viktig. Vi fant skarelaget med kantkorn under opp til ca. 1300 moh. Det virker som skarelaget ikke eksisterer høyere enn dette, og dermed er ikke problemet lenger tilstede. Dette laget er mindre viktig.

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. • Easy to trigger • 2 - Medium • Some steep slopes N, NE, E, W, NW above 800 masl • Vi har vært i nordlig sektor, men antar at problemet er til stede i alle himmelretninger. Ferskeste flak ligger i nordlig sektor Vi gikk aktivt ut for å finne fokksnø problemet. Dette har vi ikke observert eller funnet

Avalanche Problems

• Buried weak layer of faceted snow near the ground • Within a meter • A big and identifiable crystal in the weak layer. • Easy to trigger • 2 - Medium • Some steep slopes N above 800 masl

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • Difficult to trigger • 2 - Medium • Few steep slopes N, NE, E, W, NW above 1000 masl

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • The overlying slab is soft. • Difficult to trigger • 2 - Medium • Some steep slopes N, NE, W, NW above 800 masl

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • The overlying slab is soft. • Difficult to trigger • 2 - Medium • Many steep slopes N, NE, E, SE, S, SW, W, NW above 800 masl • Brudd i dette laget er rufsete og laget er tykt, samt at det ligger på bakken der steiner og vegetasjon vil hindres stor bruddforplantning.

Avalanche Problems

• Dry slab avalanche • Buried weak layer of faceted snow near the ground • Within a meter • 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 • Some steep slopes N, NE, E, SE, S, SW, W, NW • Svake laget finnes i alle himmelretninger. Veldig stor variasjon i snøen over det svake laget. Mykere lag under tregrens, over tregrensa har laget bundet seg litt bedre. Variert tykkelse på snølaget etter hvor vinden har lagt fra seg snøen

Avalanche Problems

• Dry slab avalanche • Buried weak layer of new snow • Difficult to trigger • 1 - Small • Few steep slopes N, W, NW

Avalanche Problems

• Poor bonding between layers in wind deposited snow • Within half a meter • Some steep slopes N, SW, W, NW above 1000 masl

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • The overlying slab is soft. • Difficult to trigger • 1 - Small • above 1000 masl • Ubunden løs snø i skog, fokksnø over tregrense, ca 1000 moh. Observert i SørVestvendt heng, ikke vært tilstede i andre eksposisjoner.

Avalanche Problems

• Dry slab avalanche • Poor bonding between layers in wind deposited snow • Within half a meter • The overlying slab is soft. • Easy to trigger • 1 - Small • above 1100 masl

Avalanche Problems

• Buried weak layer of new snow • Within half a meter

Avalanche Problems

• Dry slab avalanche • Difficult to trigger • 1 - Small • Few steep slopes NW • Nedbør som snø frå søraust