After a late winter and non-existent spring, and a hot and cold summer, it was anyone’s guess as to how the regimen of our glaciers performed over the past year.
Adding to the mystery was last year’s significant slow-down in the recession of Wedgemount Glacier, which was credited to the arrival of the record 1999 snow pack in the glacier’s accumulation zone to (or near) the glacier’s snout as a “kinematic wave”. So, was more of the wave to come, with a possible halt in snout recession, or was it only a one-year wonder? No such wave arrival had yet been detected at Overlord Glacier; would it show up this year?
On the Labour Day weekend we hiked the Musical Bumps route to Russet Lake — a busy weekend there, with 15 tents pitched around the cabin! Descending next day to the toes of the glacier (it has two snouts on its south lobe) the measurement (–8.1 m, –4.7 m) gave an average 6.4 metres’ recession, one metre less than last year, with both toes showing less recession. Encouraging, but not a big enough reduction to suggest an arrival of the wave — perhaps next year.
As for the distant north lobe, fronted by a small pond, it still remains in an upstream position relative to the snouts on the south lobe.
One weekend later saw three of us push our packs to Wedgemount — only seven tents were set up during our presence, with three at lakeside at the new campground near its east end. A larger than ever rock window piercing through the glacier snout suggested immediately that the glacier had reverted to full recession mode.
Indeed, our measurements on Sept. 6, 2008 showed that to be the case, receding a whopping 19.9 metres, as compared to only 2.1 metres for the year previous. It was disappointing to be sure; the wave arrival of last year was only a brief interlude in the overall staggering regime of recession, which has averaged 13.2 metres/year, over the last 108 (+/–5) years.
However, the glacier is on moderately sloped terrain and an equilibrium altitude will be reached; that is, at a higher and cooler elevation summer recession at the new terminal position will be countered by continual glacier movement to match what is lost by summer meltdown. It is not on death row by any wild stretch of the alarmists’ scare mantra about the effects of global warming! However, the terminus of the glacier will likely be between 2,000 and 2,200 metres’ elevation, instead of the historical position at lakeside (1,860 m).
Of more concern to we naturalists was the total absence of any recent sign of the presence of the Rocky Mountain goat herd at the toe of Overlord Glacier — no dust bath depressions and no recent hoof prints. Was there a calamity over the winter, or unusual predation or disease, or has the herd moved to a new location?
However, one goat was seen above the Wedgemount trail, north side, on the alpine meadows of Mt. Cook. In 35 years of surveys at Wedgemount this is only the second or third time we have seen goats there.