Wednesday January 30, 2019
Cornice Fall, Loose Wet, Storm Slab
Travel & Terrain Advice
Keep a keen eye on what actual type of precipitation that falls Thursday into Friday. Weather models are not in agreement at this point so do your research and plan according to what actually takes place (rain vs snow). Give cornices a wide berth from above and below as they get additional loading from rain and or snow.
A few loose wet avalanches have been seen falling off steep rocky faces on solar aspects at all elevation bands (BTL TL and ALP) up to size one, with recent day time heating.
Additional loading by new snow and or rain will increase the likelihood of cornice failures. Cornices do exist in the TL and ALP over NW-NE aspects. If they fail (though triggering is only possible to unlikely) they have the potential to be up to size 2.5.
With the potential rain in the forecast be on the look out for loose wet avalanches (especially from steep rocky terrain where the snowpack is thin). These avalanches may be size 1 to 1.5, will mainly be in the BTL and TL, and will be found on all aspects. Triggering is likely during the rain events, if they do arrive (fingers crossed it all falls as snow instead).
Some weather models show the next system with all snow (lets hope those ones are right). If it all comes as snow then there will be a potential for storm slab avalanches up to size 2 on all aspects in the TL and ALP. Human triggering will be possible to likely as the new snow may not bond well to the current crust that caps our snowpack. Moderate winds may transport this snow so extra care and attention should be given to NW aspects.
Spring seams to have arrived once again to the island snowpack.
|Surface||Thin non supportive melt freeze crust remains intact on non solar aspect and melts during the day in the sun|
|Upper||approx 20-30 cm of well settled snow over a beefy thick old crust.|
Spring like weather and snow conditions. No new snow has fallen in the forecast region over the past three days. Temperatures have been mainly above zero and have been as high as 10 degrees during the day time up in the hills with a slight temperature inversion.
Wednesday - mix of sun and cloud, potential light rain late in the day/evening, temps 2 to 7 degrees, winds Light SW, freezing level 2400-2700 m.
Thursday - light rain during the day changing to light to mod snowfall overnight, temps 5 to -1 degrees, winds light SW rising to moderate S, freezing levels 2500 dropping to 1100 m.
Friday - light to moderate snowfall early on, tapering off during the day to light flurries, temps 0 to -4 degrees, moderate SW winds, freezing level 1200 to 900 m.
Posted on Wednesday January 30, 2019 by Bill Phipps