24-25

We went into the Lawnmower in the Deep Creek area. Although Kyle and Haylee had skied in the zone, this was my first time there. For me this was a terrain and snowpack familiarization day. First impressions, that is a scary piece of avalanche terrain and a beautiful area. We skinned up the northwest ridge system and dug two-thirds of the way up and again at the top. In our snowpits, we tried to capture a good picture of multiple elevation bands that encompass the potential starting zones of the run and develop a picture of what we might encounter. Snowpits were 190-265 cm deep and largely resembled what I have seen in the northern Gallatin Range. From my understanding, this is an unusually deep and strong snowpack for the area. The basal facets were the most concerning layer in our 190cm pit (1000' vertical below the top). These were 1 Finger minus to 4 Finger plus hardness and rounding. We just dug to the dirt layer on our upper pit. There was 50-70 cm of settled new snow from this weekend's storm cycle. We got ECTN15 results at the interface below the recent snow (see attached snowpits). 

With no signs of instability, a strong snowpack structure, no recent avalanche activity in the visible terrain around us, calm conditions/ no wind-loading, and stable results in our snowpits, we choose to ski the main run. We did discuss that due to the nature of the terrain, each skier would be effectively solo for periods of time because there are limited areas to stop that aren't exposed to the avalanche hazard. 

One skier triggered a very small loose snow avalanche that ran 50 vertical feet at the top of the run. Other than that, the descent was uneventful. 

Temps at the car when we got back at 3 PM were 37 degrees. With sunny skies, the snow on south and west-facing terrain was getting moist and sticky, but we did not observe any wet snow activity. 

We were split boarding south of Cooke City today, up to terrain around 10'000', and finding good snow stability.

Weather was mostly cloudy in the am, partly cloudy in pm.  Light winds from the SW.

No fresh avalanche activity observed.  Attached is a photo of the only sign of a recent avalanche we could find.  (an old crown on an East aspect at 9600').

No collapsing no cracking.  

Storm snow:  was measuring the HN to be around 50cms at 8500', and 70+cms at 9500'.

With a snowpit attached from a E, NE aspect around 9500'.  CTN.

Wind effect:  significant in localized places, from the St. Patrick's Day event.  Wind drifts were not sensitive where we were traveling.

Location: Mount Maurice 

Aspect: N

Elevation: 7,600'

We found a 100cm deep snowpack. In our pit, we got an ECTn13 at 65cm on a melt/freeze crust. We found a layer of facets at the ground that was 5-10cm thick, but we were unable to impact that layer in our tests. We noted other melt freeze crusts and the Feb 4 dirt layer between the new snow on the surface and the layer of facets at the ground.  

We saw a handful of avalanches above treeline terrain that seemed to be wind slabs. However wind and snow had obscured them and I suspect there had been a lot more. 

In the last five days, this area has received snowfall containing 4.5-5.3 inches of water which has settled to about 3 feet of new snow.

In the last five days, this area has received snowfall containing 4.5-5.3 inches of water which has settled to about 3 feet of new snow. Winds last sunday night from the southwest reached speeds up to 80 mph before easing, but then they blew from the north today.

We saw a handful of avalanches above treeline terrain that seemed to be wind slabs. However wind and snow had obscured them and I suspect there had been a lot more. 

No cracking in the new snow and one possible collapse. Interestingly - My stability test scores had actually improved since Friday when there was less new snow. They broke and propagated just under a crust under the new snow. ECTP12's on Friday. ECTN & ECTP25 today. The reason is that they have been breaking on old, broken snowflakes....not facets.

Key points

• The new snow seemed mostly stable on sheltered slopes
• Wind loading is the main issue.
• With this kind of loading, it often finds weaknesses in the snowpack. I don't expect any moster slides, but also wouldn't be surprised to hear of one being triggered if tomorrow were a busy weekend day with lots of people out
• Avoid alpine terrain above treeline where winds have drifted lots of snow. Avoid hanging out in runout zones of big paths

The snow ranger crew was riding around the Bridgers today and we spotted this slide in the bowl to the south of Hardscrabble peak.  It looked fairly recent (last 2 days) but a little hard to tell due to the new snow since yesterday and blowing snow today.  Photo: USFS Snow Rangers