Hi Sierra Nevada aficionados and enthusiasts,
Quick update to our last report on July 1, as things in the high country are changing quite rapidly. As we have been reporting, the Sierra remains in a steady stream of daily thunderstorm activity from monsoonal air flow and warm, moist air rising that condenses clouds, resulting in precipitation and electrical activity. Precipitation has been in the form of intense short or, in some cases, up to a couple sustained hours of rain or hail. High and low temperatures continue to fluctuate wildly.
All of this is contributing to a high degree of instability in the Sierra. Our last report talked about a massive rockfall event on Cloud’s Rest. On
July 4th or thereabouts, an 800 cubic meter flake exfoliated from the Regular Route on the Northwest Face of Half Dome in Yosemite, rendering the route unclimbable (at least for now). More details on the Supertopo forum, where the story emerged, about how a team of local Eastside climbers had their upward progress thwarted unexpectedly. Park geologists say that the frequent rains likely contributed to this mass wasting event. Find out more updated info from the Park on this event here. In the High Sierra, the rains are having similar effects. We witnessed a house-sized chunk of granite peel of of the north side of Bear Creek Spire after a thunderstorm a couple weeks ago. Couloirs in the Sierra are seeing signs of a lot of smaller rockfall. Even a golf ball sized rock traveling at speed can be deadly, and what we are seeing is a sign that the mountains are more unstable than usual for mid-July. We consider the U and V-notch Couloirs in the Palisades, for example, to be out of reasonable condition for climbing at this time.
For mountain travel in general, check the weather forecast before you go. It’s not very accurate most of the time, but it can give you an idea about what you may be getting into. Somehow weather forecasters can be completely wrong more than half of the time and still keep their jobs. I guess it’s because they are the best we have. Most of us get complacent and expect sunny days for weeks at a time in the Sierra, but we are seeing a very wet extended period that may last well into summer this year. Plan for the best, and prepare for the worst. Hope to see you out in the high country, or down in the lower country as the case may be. ~Howie