With multiple shots of new snow and moderate winds out of the south your primary concern will be windslabs near ridgelines, steep gullies and roll-overs at tree-line and above. These windslabs were isolated and fairly small yesterday; but, surprisingly sensitive. Approach steep terrain with caution today as our new snow will likely slide easily, it's not real deep yet; but, in loaded locations it will shed easily from the older snow surfaces and may be enough to take you for an unexpected ride.
The new snow we have picked up this weekend is light and loose in areas that aren't exposed to the wind. In terrain steeper than 35 degrees you can anticipate the upper 5-10" of snow will slough easily off the surface. This problem is often benign but worth paying attention to in steep terrain laden with cliffs and obstacles.
Yesterday I recorded winds out of the south at 10-15mph on ridgeline locations. Not crazy by any means but enough to transport and pack the new snow into slabs in areas exposed to the wind. I easily triggered a windslab on Flatiron that spread 50 yards down and across the hill. Be very alert today on northerly aspects especially below ridgeline where the snow has drifted in, you may be surprised by a slab that could be enough to take you for a ride! The new snow is resting on crust above treeline, at treeline and below the new snow is likely resting on a layer of slick surface hoar, anticipate it to move easily this weekend.
Here's the kind of thing you may see today in gullies and below ridgelines on northerly aspects. Give it some respect.
Here lie da nitty gritty details! This week we have been blessed with multiple small doses of snow. 1-2" inches each day or night has left us with some pretty decent riding conditions finally. With our existing bed surface of crust and surface hoar this is actually a best case scenario for the riding and the stability. A big dump of snow right now would cause some pretty sensitive avalanche conditions with our crust/surface hoar combo, so slow and steady winds the race. I will reiterate the wind slab issue, the moderate winds out of the SW and SE caught me by surprise yesterday with the amount of drifting that had taken place as I crept out into more open terrain. After seeing lots of cracks forming near ridgeline I found boot deep drifts that were shooting cracks across the slope with ease. Had I been in steeper terrain I think these cracks would have easily created a small avalanche. Digging into the snow was interesting. In the Purcells you will find the rain crust from January 13th is much thinner than that of the East and West Cabinets. It is also harboring some weak crystals that may give us a persistent slab problem in the future (if we ever get a big dump of snow!). Right now I would focus my concern on the surface conditions as that is where you will likely find trouble out there. With the crust layer and widespread surface hoar at treeline and below we have poor conditions for new snow to bond with. The top layer of snow will move easily and I would approach steep terrain with caution today. Triggering small slides is likely out there; but, the problems are pretty predictable and easy to manage. Just take a minute to assess consequences of getting rolled by a small slab before jumping into any steep terrain and avoid areas where the snow has been loaded by the southerly winds.
