Northern New Mexico

Expect the avalanche danger to rise to considerable today if the forecast verifies as new snow and wind will create dangerous avalanche conditions at upper elevations. Wind slabs may not be bonding well to old existing surfaces and will continue to grow in size throughout the day as continued snow and moderate to strong W/SW winds drift snow into stiffer more reactive slabs. Deeper down in the snowpack,  persistent slab avalanches remain a concern primarily in the top meter of the snowpack with facets that formed around crusts during the high-pressure periods at the end of February and early March. Avoid steep slopes where you find 10 or more inches of new snow or obvious signs of instability like cracking.    

Finally a return to winter after days of warm temperatures and sunny skies.  Snow started falling late last night with 4 to 6 inches of snow early this morning with about a half an inch of SWE. Southwest winds have been in the 15 - 25 mph range with gusts in the 30's.  The National Weather Service has us under a winter weather advisory through this evening with an additional 7 - 13 inches of snow forecasted by Monday morning with winds increasing gusting into the 50 mph range.  Continued snowfall is expected through Tuesday where snow totals could approach close to 2 feet across the higher terrain. As is typical with springtime storms, expect this storm to have more of an elevational effect with higher snowfall rates at upper elevations and less snow at lower elevation bands. Unlike last week's storm, we are back to our normal loading pattern with W/SW winds increasing today as snowfall picks up this afternoon into the evening. Expect rising and changing avalanche conditions avalanche conditions during the day.  

New snow will be the biggest concern today especially above and near treeline where new snow will be falling on crusts that formed during the recent warm period and near surface facets on northerly shady aspects. With moderate to strong W/SW winds we expect most of the slab formation to be found today on the NW -N - E aspects on the leeward sides of ridgelines at upper elevations.  As snow continues later today through Monday and coverage become more widespread we'll be shifting the avalanche problem to storm slab and extending it to lower elevations.  Early reports this morning are that more snow is at higher elevations so don't be fooled by our bottom-up approaches here if you go from areas where there is relatively little snow to all of sudden start zones that have over a foot of snow.  

There's less certainty when it comes to our persistent slab problem, faceted crusts and buried near surface facets from our late February and early March dry periods continue to remain in the top meter of the snowpack.  We ultimately don't have many human triggers in our backcountry compared to other areas in the west and our last storm was not that significant with just incremental loading so it's hard to gauge how reactive these layers will be.  If extended column tests are any indication, where these layers continue to fail with easy to moderate force then we should see these layers become more reactive if the forecast verifies and we do see upwards of a foot plus of snow through Monday with wind. Before committing to a slope, take the time to dig a pit and see if these weak layers are present around crusts or in the top meter of the snowpack. 

Deeper down in the snowpack depth hoar and basal facets continue to remain present in shallow snowpacks (< 1.5m) and have mostly been lying dormant during the prolonged periods of high pressure.  With each significant storm this year we've seen these layers become more reactive which includes northerly aspects below treeline where the snowpack continues to remain shallow. The last real significant loading event happened at the end of February when we had a large avalanche that failed near the ground, so we'll see if these deeper weak layers become more of a concern as snow totals stack up by Monday. 

Winter's not done with us yet, but with that will come a rise in avalanche danger as we could see close to 2 feet of snow by the time the storm makes its exit Tuesday.  If you are getting out expect to find increasing and changing avalanche conditions over the next several days.  Fight that urge to chase powder in steep terrain, as we haven't seen much for powder skiing in the last month.  Northerly and east aspects will be the most suspect today, but you should find safer skiing and riding conditions in wind-sheltered lower-angle terrain.