h1

A short weather window for station repair

November 10, 2011
antarctic peninsula, moutnains, glaciers, and clouds

The mountains of the Antarctic Peninsula peek through the clouds. Photo courtesy Ted Scambos.

Ted writes:

As mentioned, this year’s expedition is all about repairing existing stations and setting up one new one; yesterday we completed the first of these repair missions. The site in question is arguably at the eye of the storm for ice shelf break-up, near the center of the Scar Inlet Ice Shelf, a remnant of the Larsen B ice shelf that disintegrated in 2002. Since the 2002 break-up, this shelf has calved at least three major icebergs, developed several huge cracks, and has sped up, as the obstruction of the Larsen B ice shelf plate was removed. Behind it, dammed up by the Scar shelf, lie two very large glaciers, Flask and Leppard.  The idea for this part of the LARISSA venture is to set up a series of stations to record the events leading up to the next break-up. If it happens, the Scar Inlet site is going to be a very exciting place. Briefly.

The weather window to do the work yesterday was rather short. An intense storm gathered offshore of Rothera, with contour lines of pressure resembling a large dirty fingerprint on the map. Already as we were taking off, the wind coming off the ocean was brisk, and from the ground I could see dark chunky clouds skulking around the nearby ridges, spoiling for a fight.

But from up above, as always, it was spectacular. It is the undersides of clouds that are fearsome. The upper sides are glorious, and in Antarctica you have a sun-splashed pallet of azure blue, wispy and sculptured white, ethereal cyan, and impossibly sharp black-brown, as sky, cloud, windswept or fractured ice, and rock form an ever-changing composition. A moonscape dressed in lace.The Antarctic Peninsula will someday be a world park of some kind, I am sure of it. It is breathtaking, and beautiful, and dynamic, and solemn all at once.

We flew past both the Larsen C and Larsen B ice shelves. Koni Steffen (a.k.a. Fearless Leader, and both words apply fully), graduate student Dan McGrath, and Chilean scientist Gino Casassa are now camped on the Larsen C, surveying the ice there at an earlier stage of response to climate change (the Larsen C is south of the Larsen B, and slightly cooler).

The Larsen B is closer to the point of destruction, and you can tell just by looking at it. I mentioned the huge cracks already, and there are massive crevasse trains where the large glaciers emerge from the mountains. But it’s more than that: the entire central shelf is a fine network of narrow fissures and slots, and in warm summers the entire area is covered with shallow melt ponds. The last intense melt season was 2006. If that season happened now, with the additional cracks and faster flow, I think we would see a disintegration.

Our pilot, Doug Cochran, flew several circles around our station; it was surrounded by these narrow spiderweb cracks. Last year, with less snow and more early melting, it was impossible to land here. Exposed cracks were everywhere. This year, the crevasses were still covered by icy spring snow. Eventually we gambled on one path, right along a flag line that we had installed when we first put in the station, in early 2010. It worked. Malcolm Airey,a BAS general field hand, and an expert climber and outdoorsman and I skied 300 yards to the site, roped and loaded with “jingly-janglies” (the UK slang for climbing gear: they say this phrase with complete British seriousness). We replaced the weather station and the main processing box including a much better communications system for getting the data off in a hurry, and we were done: 90 minutes.

True to forecast, the storm broke upon Rothera just as we were landing. Within minutes, we had 50-knot winds and clouds of blowing snow everywhere. Dragging our gear back the short distance to the base was far more arduous than the real work on Scar Inlet. This evening, the wind is howling, ice-choked waves are crashing against the coast, and the building is shaking (60-knot gusts, I’m told).

But we’re in the pub, enjoying the events of the day.  And fearing the walk back to the dorm building.

Advertisements
%d bloggers like this: