April 15

We got the Alta express bus at 7:54 in hopes of arriving early enough to find some decent snow before it went off. Broke a trail up Flagstaff and descending the Two Dogs slide path.

The first and second runs were in dense but dry snow.

Weather:

It was overcast, with some patches of sun especially after noon. Moderate temperatures. Winds were from the west at less than 20 mph.

Snow:

There was 4-6” of dense snow above 8’500’ with decreasing amounts as elevation decreased. It was resting on a variable old surface crust, stronger on sun exposed and weaker on the shady.
Below about 8’000’ the snow was saturated from rain and the new snow was quickly absorbed. There were areas at that elevation and below with isothermal snow off trail.
There was a little natural activity from the storm but, that increased with the patches of sun, heating and greenhousing. Skier triggered activity also increased.

We watched point releases off the rock slabs on Cardiac ridge run in front of and behind a couple of traversing skiers causing a route variation. Another point release overran the track shortly after. A traverse along the southwest facing initiated a slide into Toledo bowl, perhaps twenty feet wide, which over ran an up track there. Numerous large rollers were initiated on the Holy Toledo descent, also occurring on the power line and lower snowfield above the old mill on the exit.

Seeing that the snow was off, we bailed, rollers and small wet slides chasing us outta Cardiff.

Bottom Line:

There was a density change, just above the old surface, active early in the day. That settled with heating, which also decreased the bond of old and new snow increasing the wet activity, both natural and human triggered. This activity should decease with cooling, especially if the skies are clear, reoccurring if heating is present tomorrow. Wet slides at lower elevations would lesson and increase for the same reasons. I would not expect an increase in glide or full depth activity without significant warming.

April 17

Location:

I took the Bowman trail to Yellow jacket continuing to the ridge and descending all the way out the gully to the Porter Fork road.

Weather:

Snow, heavy at times. Moderate temperatures. Winds from the west-northwest, gusting into the 20+ mph range. Stronger with elevation gain.

Snow:

There were a couple of inches at the beginning of the day. 4-6 more fell while I was out, some quickly absorbed and settled, with the warm old surface. The old surface was cooling and crusting as temperatures cooled and snowfall continued. Cracking was observed in wind drifted areas near the ridge although the angle wasn’t steep enough to induce movement. I would expect the drifting to be active in areas more widely loaded.

Bottom Line:

Dense snow on a firm crusted old surface combined with heavy snowfall in a short period will probably result in another active spring cycle during and immediately after the storm. I’d expect to see some natural activity within the new snow. The lower elevations had a mushy old surface, which was gradually refreezing. If enough snow falls to insulate, preventing further freezing, wet slides would be expected in steeper terrain.

 

Home Gallery Journal