Category Archives: skiing|southern california

Mountain Weather

Orographic lift, waves, and turbulence over the San Jacinto Mountain Range
Orographic lift, waves, and turbulence over the San Jacinto Mountain Range

After last Sunday’s record-setting storm in Southern California, and the cool, unsettled weather during the week, we expected snow conditions on Mt. San Jacinto to be even better than on previous trips this March. But snow conditions — especially backcountry snow conditions — aren’t always what you expect. The new snow, maybe a foot of it, was as thick as wet concrete. If we’d had a little kiwi fruit flavoring, it would have been perfect for shave ice.

A mountain wave cloud near Toro Peak
A mountain wave cloud near Toro Peak.

Even if the snow wasn’t what we had hoped for, the day was extraordinary. Another weak front was moving into Southern California and the strong onshore flow ahead of the front was creating several kinds of interesting mountain weather phenomena — some common and some not so common.

Riding up the tram, we could see plumes of dust blowing across the desert floor east of Banning Pass, and a stack of lenticular clouds hovered over the mountains east of San Gorgonio Mountain. It was breezy at the upper tram station, and from the walkway descending to Long Valley, we could see rimed trees on the southeast side of San Jacinto Peak.

Video of sheets and filaments of turbulence-induced cloud on San Jacinto Peak.
Video of sheets and filaments of turbulence-induced cloud.

We skied up a beautiful untracked drainage south of the Round Valley trail, and eventually worked our way over to Long Valley Creek and then to Tamarack Valley. We were almost to the top of the steep step above Tamarack Valley, and had paused for a moment to look around. There was a distinctive wave cloud to the southeast, and the lower cloud deck was beginning to engulf Toro Peak (8716′). I turned to continue up the slope, and as I looked up, the first of a series of tumbling and twining filaments of gossamer cloud swept past in the turbulent west-northwest flow (video).

Six months ago, also before the passage of a cold front, I’d seen similar clouds on Boney Mountain, in the Santa Monica Mountains. In that case and here on San Jacinto, a moist layer in a stably stratified westerly flow was being lifted over a mountain range. Depending on whether the flow remained laminar, or became transitional or turbulent; a wave cloud, transient wave cloud, or these turbulent thin sheets of cloud might form. In each case the atmosphere was becoming more moist and the clouds were precursors to the formation of a more widespread and persistent cloud layer.

Cygnus Loop Supernova Shockwave
Cygnus Loop Supernova Shockwave

These vaporous, turbulence-induced clouds bear a striking resemblance to interstellar molecular clouds. Both appear to occur in a high-Reynolds-number regime, and each appears to consist of a cohesive, thin sheet of condensate that can be stretched, sheared, undulated and torn. As in the case of its interstellar counterpart, when viewed edgewise, the clouds look like they are comprised of thin, web-like filaments.

The title photo was taken a little below the summit, after ascending the peak. It’s a view to the south, past Jean Peak (10,670′) and Marion Mountain (10,362′), and shows the terrain induced uplift, waves, and turbulence over the San Jacinto mountain range. The flow is from the right to left.

Back to San Jack

After skiing Mt. San Jacinto (10,834′) last week, Charles and I decided to take advantage of the good snow and ski the peak again today. Warming temperatures had thinned the snowpack a bit, particularly on the flats in Long Valley (8400′), but there was still plenty of snow.

The temperature was a little cooler than last week, particularly on the summit, where a brisk west wind increased the wind chill. I didn’t dig my better gloves out of the pack, and the light (knit) gloves I used for skiing up were like wearing no gloves at all. After spending fifteen cold minutes on the summit, I bailed to the south side of the peak, near the summit hut, and warmed up.

Once again, there was outstanding skiing on the sun-warmed slopes to the south and southeast of the summit. The surface of the snow had been transformed into a velvet-like layer of fine-grained corn snow. You couldn’t pick a bad line, and Charles and I would yell at each other, “you’ve got to see the snow over here!”

Conditions were more variable in the trees on the east-facing slopes above Tamarack Valley, but there were still some excellent sections out in the sun. Threading our way through the trees on the low angle slopes leading to the Round Valley Trail was fun, and in an peculiar way, so was skiing the well-traveled snowshoe track down the trail to Long Valley.

The title photo is of Long Valley Creek below Round Valley. As the snowpack melts, deep wells and moats typically form along streams. These can be anything from an inconvenience, to a life-threatening hazard that is impossible to cross. Snow bridges melt from below, as well as above, and are difficult to evaluate. It can be unnerving to cross a large Sierra creek on a snow bridge in the Spring, when no other option is available.

Here are a few additional photos. Click for a larger image and description:

Round Valley Trail

Bowl Below Miller Peak

Summit of Mt. San Jacinto

Good Snow, Great Weather on Mt. San Jacinto

Drainage below Tamarack Valley

If you were going to pick the most pleasant conditions possible to ski San Jacinto Peak (10,834′), today’s weather would be hard to top. The midday temperature on the summit of the peak was around 40-45 degrees. Winds were light, and it was pull-up-your-sleeves warm — but not broiling — most of the way up the peak.

There was still a lot of untracked snow from last week’s storm, and overall the snow conditions were very good, especially on the steeper, sun warmed slopes southeast of the summit, and in the trees lower on the peak. Here are a few additional photos. Click for a larger image and description:

Cornell Peak Above Tamarack Valley

East Ridge of Mt. San Jacinto

Below Summit of Mt. San Jacinto