September 26, 2013

Baird Glacier Retreat Initiation, Alaska

Posted by Mauri Pelto

baird 2015

Sept. 2015 Landsat Image.  Note icebergs in new lake as Baird Glacier begins retreat.

This article was written in 2013.  A new image from 2015 has been added above indicating further retreat of the terminus and lake development at the terminus as was postulated would happen in 2013. Baird Glacier drains the west side of the Stikine Icefield in southeast Alaska. It is the only glacier of the Stikine Iceifield that has not retreated significantly since 1960. This is similar to the Juneau Icefield where only the Taku Glacier has not retreated. From 1887 to 1941, the advance totaled about 1 km and from 1941-1980 it advance another kilometer. The terminus had not changed from 1980-2010. In 1984 I had a closeup look at the terminus, it was heavily debris covered and lacked crevassing. This indicated a limited velocity, yet the ice was clearly quite thick, and it would take considerable melting to initiate retreat. In this post we examine Landsat images from 1990, 2005 and 2013 to see how the terminus is responding to climate change. The blue arrows indicate the glacier flow in the Barid Glacier System. Just above the terminus the main Barid Glacier is joined by the North Baird Glacier. About 15 km upglacier of the terminus are two glaciers Witches Cauldron (WC) to the south and Oasis to the north that the Baird Glacier is flowing into instead of being fed by them. This has been the case for sometime. Tbaird glacier ge copy

In 1990 the Baird Glacier is sitting on an outwash plain, with no lake at the terminus. The North Baird Glacier was 1100 meters wide at the yellow arrow, just before joining the Baird Glacier . The main Baird Glacier is 1350 m wide at the pink arrow. By 2005 the North Baird Glacier is 900 m wide at the yellow arrow, and the Baird Glacier 1200 m wide at the pink arrow. The terminus appears unchanged in 2005. By 2013 the North Baird Glacier is just 700 m wide at its junction at the yellow arrow and the Baird Glacier just 1100 m wide at the pink arrow. The narrowing of both indicates less ice flow to the terminus, which will lead to retreat. In 2013 two lakes have appeared at the terminus, red arrow. The terminus has begun a measurable retreat, the lakes are 400-600 m across indicating. There will be a continued expansion of these two lakes and a significiant retreat of the main terminus will ensue. This will lead to the separation of the North Baird and Baird Glacier. Upglacier in the Witches Cauldron a series of supraglacial lakes have begun to form as well. Larsen et al (2007) using repeat laser altimetry note that North Baird Glacier in its lowest 10 km from the junction with Baird Glacier was losing 2 m per year in ice thickness. From 2000-2009 the thinning rate is even higher, with Baird Glacier main trunk losing 10-20 m in thckness in the lowest 20 km Larsen et al (2009). Baird Glacier is joining the rest of the Stikine Icefield is already in retreat, Sawyer Glacier, Patterson Glacier and Great Glacier.
barid glacier 1990

1990 Landsat Image


baird glacier 2005

2005 Landsat Image

baird 2013

2013 Landsat image

baird 2015

Landsat image 2015

witches cauldron