Photos From the Field

Buck Ridge Instability Buck Ridge Instability -Dec 21, 2014

The new snow is creating unstable conditions in our advisory area.  Eric looks at small-grained facets (stripe in the snow) at Buck Ridge where we easily got our stability test to propagate (ECTP 11). This recipe of new snow on top of weak facets or surface hoar is found throughout southwest Montana.  We made a video and snowpit profile at this location.  Photo: GNFAC
 

Sage Basin Surface Hoar Stripe Sage Basin Surface Hoar Stripe -Dec 20, 2014

A stripe of weak surface hoar was obvious in the snowpack. It will be ready to produce avalanches as soon as more snow falls or the wind blows. Both are in the forecast. See the full pit profile for stability test and pit data at: http://www.mtavalanche.com/images/14/sage-basin-snowpit-profile

Wind slabs Nothern Bridgers Wind slabs Nothern Bridgers -Dec 18, 2014

Skiers triggered multiple wind slabs like this one (6-10 inches deep) in the northern Bridger Range in Frazier Basin. Photo: Bridger Brigade

Crown Butte Avalanche Crown Crown Butte Avalanche Crown -Dec 16, 2014

This avalanche was triggered by a snowmobiler on 12-10-2014. The primary places to trigger an avalanche are places where you are most likely to hit rocks on steep slopes. Other slopes in the trees generally have a deeper and stronger snowpack. Photo: GNFAC

History Rock Snowpack - 12/14/14 History Rock Snowpack - 12/14/14 -Dec 14, 2014

Over a foot of new snow fell in the northern Gallatin Range. This nearly doubled the snowpack in this area. Fortunately the storm came in warm and the new snow bonded well to the old snow surface. Facets near the ground were moist and unreactive in stability tests. Photo GNFAC 

Thin snowpack on Lionhead Thin snowpack on Lionhead -Dec 13, 2014

Eric Knoff performs stability tests on a NW aspect on Lionhead near West Yellowstone. The snowpack is very thin and weak. Despite recent warm weather, facets at the ground persist. Additionally, the warm days combined with some clear nights have started forming small facets near the surface. Photo: GNFAC

Chimney Rock Avalanche2 Chimney Rock Avalanche2 -Dec 12, 2014

This slope was triggered by a rider on Thursday, Dec 11. Exposed rocks near by tell us the snowpack is thinner and weaker on this slope, but had just enough of a slab on it to produce an avalanche. It was triggered after the rider had already been on it several times. Photo: Anon.

Chimney Rock Avalanche1 Chimney Rock Avalanche1 -Dec 12, 2014

On Thursday, Dec 11, a snowmobiler was climbing this slope after making several highmarks when it avalanched. He was near the top, kept climbing and got off the releasing slab. His partners were parked near the bottom but facing the other way and never saw it happen. Having your sled facing away is good, but always watch your partners. Photo: Anon.

Saddle Peak snowpack Saddle Peak snowpack -Dec 11, 2014

This was one of the weakest snowpacks we found on Saddle. Facets near the ground were big and weak even though they had just started to bond to each other somewhat. Other places had a stronger snowpack. Regardless, because the snowpack is so thin, it will likely weaken when normal December temperatures return. Photo: GNFAC

Silken Falls Gully_Hyalite Silken Falls Gully_Hyalite -Dec 10, 2014

The sides of the gully are wind packed, dense slabs that are sitting on weaker facets.  It took a lot of force to intiate a fracture (ECTP, 32), but it propagated which means avalanches are possible. Photo: GNFAC