Saturday, May 21, 2016

Surging glaciers everywhere

The glaciers in the Kluane National Park, right across the border from Alaska are particularly active this year and we have been able to observe several of them. Glacier surges are spectacular. When they occur the glacier can move at up to one hundred times its normal speed and in the process most of the glacier surface becomes extremely crevassed and distorted beyond recognition. Below are some pictures. Unfortunately, they didn't turn out very sharp through the airplane windows.

The Steel Glacier is undergoing the most vigorous surge:

On the upper glacier, the ice surface has dropped be several tens of meters, leaving behind a "bathtub ring" of stranded ice.

The fast flow creates very crevassed shear margins






The Walsh Glacier is also surging. I think it's in its third year of surging now, but this is by far the most active I've seen it:





And finally a picture of Fisher Glacier. This surge might be done; it reached all the way to the glacier front.


Monday, May 16, 2016

Operation IceBridge: The Stikine Ice Field

One of the most amazing things I get to do as a glaciologist is to help survey many or Alaska's glaciers from the air, as part of NASA's Operation IceBridge. This spring we have a big program and we started at the very southern end of the state: The Stikine Ice Field. Below are some impressions.

We based our flights out of Petersburg, Alaska; one of the most picturesque places in the state. In the background, the ice field with its most prominent mountain, the Devil's Thumb, is recognizable.

 
The best-known glacier of the ice field is LeConte Glacier, the southernmost tidewater glacier in the northern hemisphere:

 
Adjacent to LeConte Glacier is Baird Glacier. Until last year, it was a land-terminating glacier. But then a big subglacial flood floated the terminus and now the glacier ends in a lake. It looks like it might be retreating for a while.

 The flood on the Baird came out of a weirdly amazing place: The Witche's Cauldron. It's in the picture below, the area in front of Devil's Thumb. A big subglacial lake forms in the cauldron and then catastrophically releases along the Baird Glacier.

On the way home we passed the Juneau Ice Field. Here is a nice shot of the Hole-In-The-Wall Glacier (on the right) and Taku Glacier (on the left). Both are advancing glaciers. The Hole-In-The-Wall Glacier didn't even exist 150 years ago, it only formed when the Taku Glacier readvanced and spilled over.

And, finally, here is our science platform. The Single Otter, piloted by famous bush pilot Paul Claus

Tuesday, April 19, 2016

Our annual Black Rapids trip

Every year in spring we fly to Black Rapids to keep maintaining a mass balance program that goes back to 1973, but that has no longer any funding support. It comes in handy to have a plane on skis! We try to do the measurements in early April, a time when interior Alaska is often blessed with stable and nice weather. We managed to find such a day last week.


Sunday, April 3, 2016

Taku Glacier seismic survey

This is the last year of our Taku Glacier study. One of the major goals was to repeat a seismic study. We drilled almost 100 holes and filled the with explosives. The resulting seismic waves were recorded on a long string of geophones and this will help us characterize the nature of the sediment underneath the glacier.

I was a bit apprehensive heading to Taku after last year's rainy field season, but it turned out fine. There was some snow on the glacier; not a lot, but enough to work with. We did have some rain, but also several sunny days and some snow. At some times rain, snow, and sunshine occurred simultaneously, in typical Southeast Alaska fashion.

On the flight out we had a nice view of the glacier, which is still advancing pretty healthily.

My colleague Andy Aschwanden took some really nice pictures: https://www.flickr.com/photos/ak64north/albums/72157666219362885

The camp on a sunny evening



Ice advancing onto the 'Oozy Flats'


Ice overriding trees at the glacier front

This section of the Norris River was blocked by the glacier last year, but not quite this time

Wednesday, December 30, 2015

The Southern Patagonian Icefield from cruise altitude

One thing about doing field work in Antarctica is that, when you think you're all done, you have upwards of a week just to get home. Two days ago we got off the ship in Punta Arenas, Chile, and now we are on the way back to Alaska. One small perk of this long flight is that we happened to fly on one of those rare good weather days and I had a window seat. So here are some pictures of the Southern Patagonian Icefield:





Monday, December 14, 2015

Some impressions of Andvord Bay and Gerlache Strait

Recently we've had some amazing weather, so the true beauty of this area was revealed. We worked all night yesterday, fixing a weather station and retrieving an autonomous glider that's been going up and down the water for the last several days. Below are a few pictures from that glorious night.


Anvers Island

The obligatory Gentoo Penguin

And for the fluid dynamics geek: Probably the most beautiful example of a Kelvin-Helmholtz instability that I've come across


Monday, December 7, 2015

One more glacier camera

Yesterday we installed the second glacier camera for this project. The day could not have been more different. Instead of sunshine we had almost continuous downpour. We did find a nice site though, under slightly overhanging bedrock, which affords us with a nice view of the other fjord arm.

View of the Laurence M Gould from our camera site.

View into the fjord