IMPORTANT: The following information is provided in good faith. Both the observation and forecasting methods used to provide this summary are not consistent with international standard. They are based in the collective experience of those providing input on the conditions, the hazards and the respective rating if provided. Due to both the spatial and often subjective nature of the observation input available, forecasting is at best an estimate. Understanding, knowledge and practise in self assessment of alpine hazards is crucial to safe backcountry travel in all alpine areas covered here.
We have had significant snowfall starting mid morning yesterday. 30 cm or thereabouts. With the preexisting surface conditions observed as icy and slick in places this coupled with a variable temperature gradient in the new snow has created a considerable avalanche hazard as observed by Falls Creek and Mt Hotham Ski Patrol. With more precipitation on its way today this hazard is continuing to build both as windslab on aspects lee to the north through to west to as low as 1600m, and as storm slab on sheltered terrain features at all elevations. Particularly during the warming period. The variable bonding with the bed surface and the cohesion within the new snow are the focus of your self assessment practise in the Alpine National Park. Conservative terrain choices are mandatory for safe travel in the alpine today and ongoing. SM
UPDATE 8am 7/10/2019: With continued precipitation and transportation, whilst below 1800m there’s been no observed natural avalanche events, patrol at MHSP have conducted extensive mitigation in bounds. and the observations are consistent with Considerable below 1750, beyond 1800m the hazard advances with continued deposition and transportation hence we are issuing High Avalanche Danger Rating regionally for NE Vic Alps.
Blizzards conditions forecast. Travel in the backcountry not recommended.
Primary hazard: Considerable Storm stab hazard exists on sheltered aspects at all elevations.
Secondary hazard: Considerable Wind Slab Avalanche Hazard exists on aspect lee to the north through to west, to 1650m.
Tertiary: Where wind scouring has or will occur, a hard ice hazard prevails on windward aspects above 1650m. Be safe out there and enjoy responsibly.
30 cm (70cm+ on drifted wind loaded areas) of fresh variable medium density snow (variable -2.5˚) sits above a low density layer of -3.5˚ sits on top of nearly isothermal bed surface(-1.5˚ surface, -1˚ snowpack). A wet bed surface has bonded well with the new snow, the density gradient is ‘wrong side up’ with some weak graupel layers observed within the snowpack.
Cloudy. Very high (90%) chance of snow showers, most likely in the morning. Possible hail. Winds westerly 40 to 50 km/h turning southwesterly 35 to 55 km/h in the morning.
IMPROVING / ONGOING / DETERIORATING
Between now and our next update a period of increasing avalanche danger will be occurring. Due to weather and a possible overloading and warming. Backcountry travel is limited to conservative terrain choices.. SM
7th September 2019: 24 cms in the last 24 hours accompanied by strong winds and a slight rise in temperature overnight, and the snowpack is showing signs of instability this morning. The avalanche danger is considerable. Wind slabs may be present on aspects lee to the west (especially at higher elevations) while storm slabs are likely to be more widespread. Stick to low angled and densely treed terrain, and be very cautious of the snowpack becoming more reactive as the day warms. Be very careful and choose your terrain wisely out there today. BB
7th September 2019: With heavy recent snowfalls and strong winds, in alpine backcountry areas the avalanche hazard is expected to be considerable today. If you travel in alpine backcountry areas today, it’s strongly recommended that you remain in low angled terrain and avoid wind loaded slopes and terrain traps. MO
UPDATE 2pm 9/9/2019: With continued precipitation and transportation, whilst below 1800m there’s been no observed natural avalanche events and the observations are consistent with Considerable, beyond 1800m the hazard advances with continued deposition and hence we are issuing High Avalanche Danger Rating regionally for NE Vic Alps.