Silver Valley & Bitterroot Mountains

Incremental snowfall and elevated winds have built fresh drifted slabs on northerly and easterly-facing slopes at upper elevations. These slabs sit directly on top of a rain crust and this firm, slippery sliding surface will help increase their triggerability, so steer clear of lens-shaped pillowy areas and adjust your travels if you see cracking in the snow. Areas underneath ridges and in gullies where these slabs are around a foot deep could produce a larger slide that would be more difficult to escape.

The rollercoaster of wild weather, challenging access conditions, and wide range in snow depths across the same forecast zones all contribute to a higher degree of uncertainty than normal.

Get it while the getting is good…but do so with a heightened level of respect and open-minded evaluation around the potential consequences of triggering an avalanche. Scarcity is the “Heuristic” descriptor or trap we’ve heard mentioned a lot in recent conversations. This is likely being introduced by limited fresh snow this season and many rollercoaster weather events that depleted or completely erased prior snow cover, and introduced challenging access to where the snow has prevailed. 

A generally snowy December - more so than North Idaho’s rendition of Prince November Rain - is a much-welcomed sight. Recent snowfall will improve riding conditions but also adds additional layers that could come unglued in the wrong terrain or where it doesn’t like what interface or layer it fell on. Limited field observations recently are due to our staff having to do more tree cutting than digging in the snow. This injects additional uncertainty around the “true” conditions - especially in our upper forecast elevations (above 6,500 feet) and precisely knowing how the new snow will behave with what’s underneath.

So here’s what we know…

1) Snowfall over the past few days is adding up nicely - especially across the northern areas and slightly less in the Silver Valley. But don’t discard new snow depths down south as the same elevated winds are forming concerning slabs there. 2) This new snow sits directly on a robust rain crust that ranges 2 to 5 inches thick. How high up this crust made it in elevation is unknown and hopefully improved access this week will help us nail this question down. 3) If you are able to climb or ride into upper elevations where the recent crust does not exist, you will likely find fresh slabs closer to two feet thick, but still sitting above another rain crust buried on December 17 - but this lower crust has already started to facet. Similar layering setup, just larger potential avalanche size.

Mid and lower elevations are where things get tricky and slightly less concerning. Mid-elevations are the goldilocks area where we have similar broad rain crusts below, but those crusts are likely thicker and recent snowfall is generally less. Then, once you transition below about 5,500 feet, snow cover diminishes quickly or remains too shallow to pose much avalanche hazards. Places in the Silver Valley at lower elevations likely need around two feet of snow for us to flip the danger tile back to LOW (1of5) from No Rating. 

Because of how wet, uniform, and slippery the December 19 crust is, provoking loose snow sluffs now emerges as a secondary avalanche hazard to contend with. These are fairly easy to manage and avoid, but don’t discount what they could do in the wrong terrain - especially above cliffs and gullies. Digging down as you travel around the mountains - especially at higher elevations - is the only way to paint a better picture of what’s below your feet. If you notice the snow surface quickly transitioning from soft to hard, you barely make an impression with your boards, or edging your machine becomes more difficult, you are likely sitting on top of a dangerous hard slab.