Photo: Baird Glacier in Thomas Bay, SE Alaska
The April edition of 48 North Magazine
includes an article I wrote on Baird Glacier in Thomas Bay, Alaska. Space restrictions caused the editor to omit a side bar on this glacier's unusual geology. Instead, I'm posting it here.
Like many glaciers, Baird Glacier has retreated and advanced several times over its life cycle. But it is unusual among Alaska Coast Mountain glaciers because it advanced during the 19th century and 20th century, while other Coast Mountain glaciers retreated.
But since 2005, the glacier has been narrowing and thinning; evidence it too is retreating. Then in 2013, two lakes appeared at the terminus, indicating melting ice - further evidence of retreat.
Photo: The terminus of Baird Glacier showing a new lake.
Think of a glacier as a river of ice, always flowing. You can also picture a glacier as a conveyor belt. If more snow falls at the top in the winter than melts in the summer as the glacier moves downhill, then it advances. But if the ice melts before reaching the bottom, the glacier is retreating.
In the case of Baird Glacier, an unusually large flow of melting ice from underneath the glacier washed loads of sediment into the bay, building up a vast outwash plain, while the glacier advanced. As a result, there has been land in front of the glacier at least since 1887 when it was first surveyed. That's what makes visiting Baird Glacier such a treat: walking on that outwash plain with its flowers and birds.
Now that Baird Glacier has joined the crowd of other SE Alaskan glaciers in retreat, we can expect it to shrink and its terminus to move uphill. And, if flooding doesn't wipe clean the land, we can expect to see increased vegetation on the outwash plain and species that haven't been there before. We think of geological processes as happening beyond our lifetime, but right now, in Alaska, and wherever there are glaciers, the landscape is changing before our eyes. It's another reason to go there.
Photo: The outwash plain of Baird Glacier provides an interesting walk
More photos on my flickr site: Thomas Bay: https://www.flickr.com/photos/ejhulsizer/sets/72157639294212954/