Alcan Highway Beginning To Crack, Washboard As Permafrost Melts And North Warms - NYT

NOT SO PERMANENT A pool of permafrost meltwater has formed along the Alaska Highway near Beaver Creek, Yukon.
By CORNELIA DEAN
Published: July 23, 2012

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But today the Alcan faces challenges that could not have been predicted when it was built. By far the biggest is permafrost, the permanently frozen ground that underlies much of the road. As the climate warms, stretches of permafrost are no longer permanent. They are melting — leaving pavement with cracks, turning asphalt into washboard and otherwise threatening the stability of the road.

Not all of the melting is due to climate change. Road improvements like heat-absorbing dark pavement alter conditions in the ground beneath, particularly if a lens of ice lies close to the surface. Merely removing roadside vegetation to uncover dark soil can have a melting effect.

Another problem is fire. “Even a natural forest fire will change the surface of the road,” leading to melting, said Bronwyn Benkert, who studies cold-climate issues at the Yukon Research Center, and who is researching highway conditions north of here, near the Alaska boarder.

But climate change is most worrisome of all. Not only is the world warming: it is warming fastest in high northern latitudes. And the problem is getting worse, with no easy solutions.

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http://www.nytimes.com/2012/07/24/science/with-warming-peril-underlies-road-to-alaska.html?_r=1