Chance discovery: Alaska Range glacier surges

Submitted by Amy Hartley
Phone: 474-5823
03/15/06

Photo courtesy of Martin Truffer, Geophysical Institute, UAF

On March 13, 2006 glaciologists Martin Truffer and Will Harrison, both of the Geophysical Institute, flew over the McGinnis Glacier. The jagged pinnacles and deep crevasses they witnessed are telltale signs that the glacier has surged.

March 16, 2006

University of Alaska Fairbanks Assistant Professor of Physics Martin Truffer recently discovered evidence that the McGinnis Glacier, a little-known tongue of ice in the central Alaska Range, has surged.

During a recent trip, Truffer noticed the lower portion of the glacier was covered in cracks, crevasses, and pinnacles of ice--all telltale signs that the glacier has recently slid forward at higher-than-normal rates. It has not been determined whether the glacier continues to surge.

Truffer, of the UAF Geophysical Institute’s Snow Ice and Permafrost Group, is having difficulty finding information on the glacier’s history. He said the glacier hasn’t been on anyone’s radar screen for some time. Much of what has been written about the glacier is that it was covered with debris after several landslides broke loose from Mount McGinnis after the 2002 Denali Fault earthquake. In fact, that’s what prompted Truffer to explore the glacier just a few days ago on a recreational snowmachining trip with friends.

"We were going to look at the landslide area and instead we saw that the entire glacier had surged. It was completely by chance,"? he said.

On March 13, Truffer flew over McGinnis Glacier in a small aircraft with Professor Emeritus Will Harrison to confirm the signs of the glacier’s surge. The glaciologists saw trim lines high up on the glacier and accordion-like crunching at its base. A surge starts high up on a glacier and then propagates in a wave down the length of the glacier.

Truffer says surging is unusual, however the Alaska Range is unique in that several glaciers located there experience it. The most well-known surging glacier in Alaska is the nearby Black Rapids Glacier, which advanced within a half a mile of the Richardson Highway in 1936.

Truffer says it’s unfortunate that little is known about McGinnis Glacier. If the latest discovery could be compared to previous records, the surge could tell scientists much more. In the meantime, the Snow, Ice and Permafrost Group hopes to send a crew to McGinnis Glacier, located about 100 miles south of Fairbanks, to observe the surge and gather data.

PHOTOS AVAILABLE AT: www.gi.alaska.edu/~truffer/McGinnisSurge/ Credit: Martin Truffer, Geophysical Institute, UAF

CONTACT: Assistant Professor of Physics Martin Truffer at (907) 474-5359 or via e-mail at truffer@gi.alaska.edu. Information Officer Amy Hartley at (907) 474-5823 or via e-mail at amy.hartley@gi.alaska.edu.