Northern New Mexico

Recent snow and very strong winds have drifted snow into wind slabs near and above treeline.  You can trigger a wind slab avalanche on slopes where you find 8 or more inches of snow.  These wind slabs could be dangerous on their own but could also step down into deeper weak layers creating a larger and more destructive avalanche. You can also trigger a persistent slab avalanche on deeper buried weak layers where the snowpack is shallower.  This will be found in likely trigger points on the margins of the slab and near rock outcroppings. It may not be the first or second person on the slope but just takes you to find a sweet spot where you're able to impact deeper buried weak layers.  Sticking to wind-sheltered lower-angle terrain without steep slopes above you will provide safer skiing and riding options today.  

A system today is staying well to our south in southern NM leaving us with another sunny and warm day up here to the north.  Temperatures this morning are in the low teens but will quickly warm into the mid and upper 30's.  It's getting to be that time of year as we look to head into March where our sun angle gets to be really intense and quickly warms up slopes.  Yesterday by mid-day southerly aspects were warming up.  We should see loose wet snow avalanches become more of a concern today, so watch for roller balls and pinwheels as these are indications that the snow surface is becoming wet.  These loose wet snow avalanches will typically start in steep terrain around sunbathed rock bands on our solar aspects and fan out as they travel down the slope.  If you notice the snow surface becoming wet, head to a shadier aspect.  It's that time of year to start bringing a scrapper and glob stopper as you transition from wet to dry snow. 

Strong winds during the Feb 7th storm stripped and scoured many slopes and loaded others. This has created pocketed areas of wind-drifted snow that are easy to identify in travels. It's hard to believe, but this wind event stripped a meter plus snowpack back to bare ground on a slope Charlie and I were skiing last week.  East aspects above treeline have seen the greatest amount of loading and will be the most suspect slopes today.  Yesterday in my travels I found these slabs to be 10 to 30 cm thick ranging from 4F to pencil hard.  These slabs were not overly reactive like we had suspected, but were able to get them to propagate on specific slopes where there were near surface facets or a facet crust combo beneath the slabs.  There was also a graupel layer present within the wind slab, but I did not find this layer to be reactive in long column tests. Surprisingly the skiing wasn't all that horrible while patching together areas of soft sastrugi making for some pleasant turns. 

Explosive control work yesterday produced mixed results with not much for results with the wind slabs. However, one result that stood out to me was in an uncompacted open and exposed terrain below treeline. This path had run earlier this year and wind loading and a more reactive slab created the right slab/weak layer combination to reawaken deeper persistent weak layers producing a size 2 avalanche that propagated 75' wide and was 2 feet plus deep putting a 6 foot debris pile on a cat track. Although not the big storm that was forecasted, the threat of triggering a persistent slab avalanche has increased with new slab formation and loading.  Below treeline, the snowpack remained relatively shallow, and weak layers have been slower to heal. At this lower elevation band, watch for steep open and exposed areas where you find wind-drifted snow. Many avalanche paths have already slid once and in some cases twice (Peace Sign).  These repeat offenders have a shallower and weaker snowpack and may struggle to handle even a little bit of loading.