Hubbard Glacier defies climate change, continues advancing

A Yukon glacier is slowly advancingtowards an Alaskan river,setting the stage for an awesome collision of natural forces.

If theglacier that originates near Mount Logan in the Yukon continues advancing at its current rate, it couldblock access to a fiord in Alaska and "strongly impact" the nearby ecosystem.

New research from the University of Kansas suggests the Hubbard Glacier could permanently dam the entrance to Russell Fiord, on the Gulf of Alaska, within 25 years.

The timeline is the "best guess" of assistant professor Leigh Stearns, whose research builds on decades of previous studies on the Hubbard Glacier. The glacier, whichoriginates in theSt. Elias Mountains of southwest Yukon, has been widely studied because of its enormous size and itsproximity to the Alaskan community of Yakatat.

Water in Situk River could increase 50-fold

Experts saythe main impact of the Russell Fjord closurewill be on the Situk River, which originates from a lake of the same name.

David Williams, project manager of the Yakatat watershed study for the U.S. Army Corps of Engineers, estimates it would take about a year for water levels in the dammed fiord to rise 40 metres, at which point glacial meltwater would overflowinto the Situk River.

"It will be catastrophic for those whopresently fish theSitukunder its present conditions because it will change the conditions drastically."

The river is heavily used by commercial fishers in Yakatat, which has a population of about 650 people.

"When you have a river that's running relatively low flow and you increase[it] by anywhere between 20 and 50 times, it's not going to leave the bed of the river or the banks the same," says Williams.

He says the lower part of the river river would likely get colder, have more channels and will be full of logs jams because of upstream erosion. Not only will this change dynamics for fish and wildlife in the area, it could make it difficult and dangerous for fishers to access the river.

Williams predicts the overflow would be mostly freshwater, because the denser salt water will remain on the bottom of the fiord.

Glacier increases in size

Stearns says the Hubbard Glacier is unusual because it has been steadily advancing for more than 100 yearsdespite warmer temperatures.The glacier isaccumulating mass near its origin faster than it's losing it in the ocean.

"It would need to warm a lot for Hubbard to start retreating, is what we're finding. Whereas, a lot of the neighbouring glaciers it only has to warm a little bit for them to become unstable."

Russell Fjord has been temporarily blocked by theHubbardGlacier twice in recenthistorybut the closures did not last long enough to overflow the fjord. The longest closure, in 1986, lasted about five months and caused fiord levels to rise 25 metres, according to Williams.

A sight to see

There could be short term benefits to the closure.ReggieKirkovich, who owns a fishing charter company inYakatat, says the last time it happened, every room in town was booked by news outlets, environmental groups and tourists wanting to visit the glacier and see the marine life trying to escape the freshwaterfiord.

"The folks that were here said it was an absolute bonzana."

Williams says the Situk River would eventuallystabilize enough so fishers could access it again and says it could even increase the fish yield in the long runby creating more spawning habitat.

He says they won't know for sure until it happens.