Thursday, September 13, 2012

LeConte Glacier

This fall I had an opportunity to go back to LeConte Glacier in Southeast Alaska. LeConte Glacier can be accessed from the fishing town of Petersburg, which was founded by Norwegian fishermen, supposedly because of the ready availability of glacier ice for cooling.

Sea lions relaxing in Petersburg's harbor
LeConte Glacier is the southernmost tidewater glacier in the northern hemisphere. I have been lucky to be able to go to some of the more spectacular places on Earth (at least as far as ice goes), but LeConte might trump them all.

At the entrance of LeConte Bay

LeConte Glacier, at the head of a narrow fjord

The glacier from our camp site
LeConte Glacier comes out of the Stikine Icefield, which hosts some spectacular peaks. Most notable is Devils Thumb, which features in Jon Krakauer's book 'Into the Wild'. It is a notoriously difficult climb, because it is exposed to so much bad weather.
LeConte Glacier with Devils Thumb
The spectacular scenery here comes at a price, and rainy and cold days are the rule.

The reason for our work lies in the fact that LeConte Glacier was the site where a study by Roman Motyka has found that significant amounts of melting occur at the base of the glacier by warm ocean water. We have wanted to follow up this 2003 study for many years, but have been unsuccessful with funding. Due to a recent generous grant from the Gordon and Betty Moore Foundation, we were finally able to repeat this interesting work.

The boat, lost among ice bergs
While one crew was doing oceanography off a small boat, we were at a camp, measuring ice flow with a fancy new radar, and recording calving with timelapse photography.

Some glacial geology: Striations carved into the bedrock by the glacier

Monday, September 3, 2012

It's winter on Black Rapids Glacier

Lee and I wrapped up a successful season on Black Rapids Glacier. We removed all summer instrumentation and beefed up the three GPS that are staying for the winter with high capacity batteries. The trip started with bad weather and new snow on the glacier, but it quickly turned into beautiful fall weather. But there is no mistaking it: winter is on the way, and a thin layer of fresh powder was coating the surface.

A view of the landslides that hit the glacier during the November 2002 Denali Fault earthquake. The coating of rocks insulates the ice from most melt. The clean ice continues to melt, however, resulting in an increasing height difference between ice and rock.