Regional Conditions for Centennial Range

Observed 125 cm snow at 8200' on NE aspect. ECT showed propagation on each crust. South aspect at 7500' had ~65cm snow depth with similar crust but less reactivity. In general observed poor structure and poor strength everywhere.

Snow above the rain crust is starting to become more of a cohesive slab. No recent avalanches were observed.

We did a short tour yesterday in the middle of the storm into the Republic Creek drainage. Skies were overcast with light to heavy snow falling at times. Winds were gusting at times 60-80 mph, enough to blow you over if you weren't careful. Variable snowpack, wet and heavy down low until about 8800 feet then it got colder and less dense but was blowing around all over the place. The new snow was setting up very slabby in places with cracking expanding outward from the skin track and storm snow easily sliding at every kick turn. We did not dig a pit and instead opted to bail out at about 9400 feet and ski tighter trees back down to the creek bottom and home. The winds had stripped snow on the windward side with some larger drifts on the leeward side. However, in the basin, winds were coming from every direction at times. Not a very scientific observation but wanted to share what it was like in the storm up there yesterday. Caution really needs to be practiced as there are dense storm slabs sitting on large surface hoar/facets that had setup from the days of high pressure and winds may have deposited large amounts of snow in places.

Rain crust is still very present in the snowpack. Two natural slab avalanches on north aspect of Reas Peak, one from recent storm and one from previous storm. Photo is from a snowmobile triggered avalanche from 1/9/21, you can see the party and one of the members riding the adjacent slope. Snowpit attached as well.

Yesterday I snowmobiled form the Keg Springs trailhead to Tin Cup Pass on Willow Creek. From the limited visibility we did not see any natural avalanche activity. We dug one pit on the Idaho side of the Centennials and found the total snow depth was 70cm and there were 2 distinct crusts in the snowpack and a fair amount of depth hoar. The pit profile was as follows:

70cm-55cm First Hardness
54cm-50cm 4 Finger
49cm-48cm Knife
47cm-25cm Fist (facets)
24cm-23cm Knife
22cm-0cm Fist (depth hoar)

Test Results: ECTN 12@49CM, ECTN 14@24CM

Seemingly unsafe snowpack here in island park. A few very firm crust layers. One facet layer near the base which propagated. Two crust layers, both knife hardness, were stacked in each other with a small amount of facets between them. This layer went on CTE 8. I wasn't able to attach it but I will send it separately. We weren't in avalanche terrain today so there were no other observations.

Road cut south facing slope of 42 degrees, triggered intentionally by a guide, shows about 12 inches of windblown soft slab on top of a faceted layer (in this case more extreme due to aspect and inclination toward the sun) but was triggered only by chopping a hand into the snow a few times. This same faceted layer (the uppermost layer of a thick faceted layer of 1-2 fee) exists throughout the snowpack.

Also, the bottom-most layers of snow are very faceted and conditions have not occurred yet to set the snow for a base. Walking around your feet go right to the ground even in areas where snow is 2+ feet deep. There are many rock/tree hazards lurking under the soft snow because of this, two people in our group damaged their a-arms.

Lower elevation plateau with low snow accumulation due to consistent wind-scouring, consists of about a foot of faceted snow with a dense wind-blown slab on top.

Both the Lionhead area and the nearby Centennial Range in Idaho have a similar snowpack. About 20-25" are on the ground consisting of weak, faceted, sugary snow. Riding is supportable, but we tiptoed around Lionhead because of rocks.Snow and wind are forecasted in the oming week. This snowpack will become unstable quickly. I expect to see cracking, whumpfs and recent avalanche activity. Small avalanhes on road cuts or creek banks are bulls-eye data that big avalanches are likely. Be careful, pay attention and stay clear of creeks and other terrain traps where even a small slide can be deadly. We made a video that outlines our concern which is posted on the Centennials page.

Observed 24" of snow in leeward aspects at an elevation of 7700'. West faces above 7000' appeared scoured and bare to the ground, limited coverage. In sheltered south facing areas where snow hadn't been scoured, a stout breakable crust existed near the surface. Old snow snow was faceted to the ground, ski poles easily penetrating dirt. Below 7000' skiing was not possible due to low coverage, relegating our party to skin on the summer trailhead in and out of Hellroaring.