The grey, two-story home with white trim toppled and slid, crashing into the river below as rushing waters carried off a bobbing chunk of its roof. Next door, a condo building teetered on the edge of the bank, its foundation already having fallen away as erosion undercut it.
The destruction came over the weekend as a glacial dam burst in Alaska’s capital, swelling the levels of the Mendenhall River to an unprecedented degree. The bursting of such snow-and-ice dams is a phenomenon called a jökuhlaup, and while it’s relatively little known in the Us, researchers say such glacial floods could threaten about 15 million people around the world.
Water released from the basin has caused sporadic flooding since 2011. But typically, the water releases more slowly, over a number of days, said Eran Hood, a University of Alaska Southeast professor of environmental science.