NASA reported that Alaska's Hubbard Glacier has been getting thicker and extending into Disenchantment Bay since measurements first began in 1895.
The curious glacier differs from many others in Alaska and around the world, which have been notoriously thinning and retreating. The researchers believe Hubbard's advance is a result of its large accumulation area. The glacier's catchment basin extends into the Saint Elias Mountains, and snow that falls into this basin melts or flows into the terminus, facilitating Hubbard's growth.
The glacier is observed to be building up a large moraine (an accumulation of debris that falls onto a glacier's surface or is pushed along as it moves), and is shoveling this collection of dirt and rocks from the Earth's surface onto its leading edge. This phenomenon improves the glacier's stability and allows it to advance more easily because thinner ice can remain grounded.
In both 1986 and 2002 the moraine has advanced far enough to come in contact with Gilbert Point and block the entrance to Russell Fjord. This has caused runoff to accumulate, leading to rapid rises in the fjord's water levels. This effect can be bad news for Yakutat, Alaska, which depends on the fjord for marine life.
"Understanding Hubbard's behavior is scientifically interesting," said Leigh Stearns, a glaciologist at the University of Kansas. "But it also has immediate consequences for the town of Yakutat."
Stearns was at a glaciology conference in Yakutat in 2002, and the effects she witnessed prompted her to look into ways to predict the glacier's advance and when the fjord may become permanently blocked. In one estimate, researchers suggested this could occur as soon as 2025, but Stearns disagrees. Hubbard is about 9 miles wide, and does not advance at the same rate across its entire area. The region that lines up with the point at which closure would occur (Gilbert Point) is believed to be more slow-moving because seawater is constantly eroding away the ice. Based on this information, Stearns predicts the gap will close around 2043, but even that estimate is not certain.
