Sawtooth & Western Smoky Mtns

You'll find several feet of recent snow at upper elevations. Variable wind speeds and shifting winds built multiple generations of wind drifts and slabs, and today's winds will continue to build these features. Older slabs will be hard to identify visually. More recent slabs will be smaller, more obvious, and more reactive. Periods of sunshine can quickly produce wet snow problems and natural wet snow avalanches. Most wet snow slides will involve only the recent snow, but deeper wet snow issues can't be ruled out in areas where the underlying snowpack is still saturated from rain on Wednesday and Thursday. 

UNCERTAINTY AND VARIABILITY

An intense series of storms this week brought significant rain to much of our terrain. Temperatures have gradually cooled since Wednesday and the rain/snow line has dropped with them. Friday's precipitation fell entirely as snow, even at valley bottoms. When you head into the mountains today you will find wildly variable conditions as you climb in elevation and change aspects. Read on. 

At lower elevations, the majority of the recent moisture fell as rain, with a few inches of snow at the tail end yesterday. Temperatures have been below freezing for 12 hours and will remain cold today. The snowpack here has had some time to drain and refreeze and triggering large slides at lower elevations is unlikely. However, if you're encountering a wet, mooshy snowpack, think about the consequences of triggering small wet snow avalanches.

As you climb into middle and eventually upper elevation terrain, you will see snow totals increasing significantly. Most of our upper elevation terrain stacked up 2 or more feet of snow since Wednesday. Strong winds blowing out of the S/SE accompanied precipitation initially. Winds eased yesterday, allowing for some lighter snow to fall generally straight down. Wind speeds will pick up today and shift to blowing out of the NW. A new generation of wind slabs will build in upper elevation terrain. Freshly forming slabs will be easier to trigger but much smaller than the huge slabs that formed on Thursday. The older, much larger slabs have had more time to bond and will be less likely to slide. However, at upper elevations where these slabs rest on weak surfaces like facets and crusts they may remain reactive. As a reminder: skiers in the Boulders (on Galena Peak and Lorenzo) were triggering small wind slabs at the start of the week, before therecent storms. 

Today will be cold and generally cloudy. If the sun doesn't make an appearance, we don't expect to see wet snow problems developing. However, it will not take much sun to bring these problems to the table. 15 minutes of direct sun can radically transform the snow at this time of year.

The loose wet and wind slab problems described above are taking place on top of a snowpack that remains wet from the recent rains. It will take some time to drain and refreeze the snowpack after the drenching it received on Wednesday and Thursday. We put a thick, snowy blanket on top of this warm, wet mess with yesterday's snowfall which helps to insulate the snow below and slows the rate at which the snowpack refreezes. 

Manage the complexity, variability, and unpredictability posed by our transitional snowpack by building a wider safety margin into your travel plans today. Pay attention to the snow you are moving through, the snow on the slopes above you, and the snow you will have to move back down through at the end of the day. Watch the cloud cover and pay attention to how much snow is being transported and deposited as the winds pick up. Be ready to step back from the plans you make, and have an exit strategy if things start to melt down.