NORTH CASCADE GLACIER CLIMATE PROJECT
2008 Field Season -Our 25th Field Season
Mauri S. Pelto
Nichols College, Dudley, MA 01571
Field Scientist:Tom Hammond: firstname.lastname@example.org
July 31-Aug. 15th:|
For the 25th consecutive year we (Brad Markle, Ben Pelto and Tom Hammond) hiked the Blanca Lake trail and this was the hardest of the bunch. Was it because of age? No. It is because of the annual new obstacles added. In 2007, it was the fall washout adding 1.3 miles to the hike. Than in 2008 that 1.3 mile road walk featured the first event right in the first 100m, over and under a dozen windfall trees. The rest of the road featured another dozen trees to hurdle-limbo, though with a pack neither maneuver is effective. The second event in the pentathlon is the same as always, 30 switchbacks with a few added tree falls as a bonus. The third event is the fording of Troublesome Creek at the Blanca Lake outlet. Of course with a largely snow covered lake this was not as warm as usual. The log jam needs some new supplements from the avalanches of the winter that did bring down some new trees onto the lake. The fourth event was the 40 degree slope with snow that steps had to be hacked into to progress with a full pack. The fifth event the normal shoreline shuffle with trees trying to push you in and the snow overhanging the lake trying to sucker you into a false step. We camped at the far end of the lake and the poor marmot village was still under snow. The glacier itself had the deepest snowpack of any year except 1999. Unlike the rest of the North Cascade glaciers which had snowpacks not dissimilar to 1997, 2000 or 2002. this glacier was buried. Not one speck of blue ice showing. We spent the next two days probing the snowpack, the thinnest cover was 5.8 feet, and most of the glacier was over 14 feet. Fortunately we worked in a cloud, or the heat could have brutal, and the mist kept our thirst down too. Anyway this glacier which has lost an average of 17 m of thickness in the last 24 years, will gain about 1 m this year. And I will note that the traffic into this area has diminished substantially, how will this
The weather cleared for gorgeous conditions on Easton Glacier. I Snowpack was good, but not great, two feet more than normal low on the glacier, average snowpack above 7000 feet and even a bit below normal by 8500 feet. Along with Joni Kincaid and Andrew Klein of Texas A&M we installed two temporary weather stations, one adjacent to the glacier and one 100 m from the first on the glacier. Results will be forthcoming from this experiment. Chris Lyles retrieved the stations later in August. We used crevasses and probing to identify snowpack at 165 locations on the glacier. This glacier had the lowest mass balance of any we measured this year. We measured ablation over the two week period on this glacier and found 41 inches of snowpack melted on Easton Glacier at 6500 feet.
Camped along Ptarmigan Ridge at Camp Kiser are only neighbors were mountains goats, we saw 43 different goats within two miles of camp. We left at 8 am on a warmish morning. Thus, Sholes glacier was soft enough to cross without crampons. After measuring snow depth across the Sholes, we passed through the Portals and began the long traverse down to the Rainbow Glacier. That's right we camped high and had to hike down. We slowly descended the Rainbow Glacier measuring snow depth down to the terminus area, still buried in snow. Fortunately the nice day allowed us to take our time, plus we had to take measurements every 100 feet, which is just about right for the next rest. Rainbow Glacier had excellent snowpack with an average of 5 meters at 6500 feet. From the top of the glacier we crossed onto the Mazama Glacier and traversed below Landes Cleaver to the upper Sholes Glacier. It is now 5 pm and legs are tired, feet are soaked. Great glissade down onto main Sholes Glacier and then ascend at a very slow pace back to camp. Sholes Glacier average snowpack was 3.4 m. Wow only 12 hours to make the circuit.
For three straight summers rain has visited us on Lower
Curtis Glacier. This year over three inches of it on August 9th and 10th. If
we take a look at the glacier over the last three years, in 2006 the main river
draining the glacier was near the west side, in 2007 for the first time in the
last 20 years the river had shifted to the center of the glacier, this year the
stream had shifted back to the west side of the glacier.
|Terminus river outlet Lower Curtis Glacier|
|Lower Curtis Glacier sideview 2006|
We returned to Lyman Glacier with a reporter and photographer from the Wenatchee World (link will be added when article published in Sept.) Aug. 10-11. The ascent of the Spider Gap valley was like a highway with people and dogs progressing up or down. From the gap we headed left, toward the glacier, instead of right along the trail to the basin. The snow slope is much gentler than it used to be, and this route does not require an ice axe any more. We descended onto the glacier and began mapping. This required traversing the width of the glacier four times.
Unlike most North Cascade glaciers which were 80-100% snowcovered still, Lyman Glacier had only 65% snowcover. The maximum snow depth had exceeded 14 feet on every glacier we had examined. On Lyman Glacier maximum snow depth was 11 feet and very little of the glacier had more than 9 feet. That means almost the entire glacier will lose its snowcover. After lunch we crossed on an ice apron below the ice cliff at the terminus. The cliff is currently 24 m high. After crossing beneath the terminus cliff we went to the 1986 and 1950 terminus position and photographed the glacier terminus and measured the distance of retreat. The retreat since 1986 has been 223 meters., 415 meters since 1950, and 720 m since 1926. given that the average glacier length is about 400 meters now. This means that 1/3 of the glacier has been lost since 1986. The glacier is still quite thick in the middle. If we could see a 24 m ice cliff above the waterline, it is certain the glacier is at least 40 m thick at the terminus, and more that behind the terminus, as the glacier slope is 22 degrees here but the slope of land exposed as the glacier retreats is small indeed less than 5 degrees. As disquieting as the loss of Spider Glacier and the retreat of Lyman Glacier was the pitiful health of the forest on the first few miles of the trail to Spider Meadows, red tinged, with sections above already having lost all their needles. The area needs a forest fire and will get one. The forest at Spider Meadows looked fine. The latter pictures also illustrate the separation between the upper and Lower Lyman has rapidly expanded in recent years and more bedrock exposure at the head of the Lyman Glacier indicates the glacier is thinning noticably at its head. Our mapping indicated 15 meters of thinning since 1988 in the mid-section of the glacier. The Lyman Glacier has retreated a total of 1380 m since 1890 or 1900. The rate varied from 8 to 21 m per year for various decades up to 1958. It retreated at a rate of 10 m per year 1958-1986 and 10 m per year again from 1986 to 2008. The current glacier length is 390 m on the eastern margin and 470 m on the western margin. The continued retreat at the 50 year retreat rate would eliminate the glacier in 35-50 years. The glacier is still quite thick and should slow its retreat once the bedrock slope begins to increase, and the minor lake calving ceases.
We finished the season at Mount Daniels a couple of nice swims in the Cle Elum River sandwiched around some warm weather on the mountain. Ice Worm and Daniels Glacier were both completely snowcovered still with the best snowpacks since 2002 on both glaciers. Lynch Glacier the lowest 200 m of the glacier was bare ice to the terminus just above Pea Soup Lake. The snowpack was deep enough on this glacier to fill even the larger crevasses on the upper portion of this glacier.