August 21st saw Park Geologist Greg Stock, assistant Colter Chisum and me heading back up to the glaciers to record their movement since July. I was happy that my gal Shauna Potocky also came along, as she was meeting with trail crews at a nearby CCC camp, just off the PCT, to give them a presentation on her recent trip to Chile.
This glacier trip was designed to be a simple, fast, and light trip: Hike in, measure movement of the stakes we put in the ice in July, and then hike out 24 hours later. All of us brought light bivy sacks just in case we had some wet weather…more on that later. One thing to note from the last month’s blog post – August 21st was the day that John Muir had placed stakes in the Maclure Glacier to do his personal research. Greg’s goal was to duplicate measurement 140 years later to the day.
Starting before 9am, we made good time and over 12 miles later Greg, Colter and I were at the foot of the Maclure Glacier by 4pm, where we met up with Yosemite Conservancy naturalist and educator Pete Devine (who is personally interested in Yosemite’s glaciers like me).
The first noticeable observation was the lack of snow on the glacier – nearly all the ice was exposed. The Maclure in July had a fair amount of snow coverage. The previous two weeks had seen temps above normal (Yosemite Valley, at 4000’, was in triple digits for nearly a week). Greg’s unease about stakes melting out of the glacier were realized when we approached the lowest stake to find it lying on top of the glacier. Greg estimated that the glacier had lost approximately 1.7 meters of glacial surface to ablation since the July trip. Ultimately – we did not put the stakes in far enough! Luckily, we had GPS locations for all the placements, plus rock cairns at nearly all of them, so we were able to find the original locations and re-drill the stakes into the ice. So, a one hour job became a four hour job when we finished right as red sunlight was leaving Maclure Peak – achieving the data gathering on par with John Muir’s August 21, 1872 date.
NOAA’s website predicted fair weather for our 2 days out. Clouds began forming overhead as we sat down for our meal. The skies were completely grey by the time we all went to bed, so we all decided to play it safe and rest inside our bivy sacks. Hours past when I was awakened by drops hitting the netting of my bivy. “No problem. I’ll just zip up the bivy and be dry while the rain falls.” The rain got harder and harder and within an hour, a steady downpour ensued. I noticed my sleeping bag was wet near one of my legs. I turned on my headlamp and to my horror; the top of my bivy sack had delaminated from the bottom! My sleeping bag was getting soaked! Thinking fast, I flipped over my bivy and used it as a basic tarp. It rained the whole night. Luckily, the temperature wasn’t too cold, so I threw on all my warm clothes and had a very wet, clammy night with maybe 2-3 hours’ sleep.
The four of us awoke at 7am. Come to find out, no one had a restful sleep. Greg got wet in his bivy and had to move out of a pool of water that formed around him. So, we shrugged our shoulders, ate our breakfast and got ready to hike over to the Lyell to measure the stakes there.
Some stakes had melted out of the Lyell, but some were still in the ice – better than expected from the previous day’s discoveries. Greg had also found two stakes from his 2010 survey that were still in the glacier, so we added the measurements of those to the five we placed there in July. Success!!
Rain clouds formed again and by the time we finished the rain was falling. Gratefully, we all descended back to the PCT safely. Greg, Colter, and Pete continued to hike the remaining 11 miles out while I stayed with Shauna near the CCC camp one more night.
Even with equipment failure and unforeseen stake melt-out, the August trip was fruitful. September’s trip is just a few weeks away. I look forward to updating you with the results from this trip. Let’s all wish for a dryer trip!