Glacier Leaping

The Mendenhall glacier, 14 miles from downtown Juneau, Alaska is doing more than looking blue and pretty while slowly slipping into the sea.  It seems to be lifting its skirts and preparing for a run, in fact. There is even a name for this, which happens nearby many glaciers as water accumulation, in the warming climate, builds up faster then the old channels can release it: jokulhlaup, is an Icelandic word usually translated as “glacier leap.”

As water builds up in [a] basin and seeks an outlet, it can actually lift portions of the glacier ever so slightly, and in that lift, the water finds a release. Under the vast pressure of the ice bearing down upon it, the water explodes out into the depths of Mendenhall Lake and from there into the river.

NY Times

Home on the Mendhenhall River is surrounded by water on Thursday, July 21, 2011.

Home on the Mendhenhall River is surrounded by water on Thursday, July 21, 2011.

This would be totally cool to see, if not for one thing:  400,000 tourists a year come to Juneau to have a look at the glacier.  It is sort of a ‘drive by’ glacier as one local calls it; no interminable mushing though sub zero temperatures or dropping out of the sky in flimsy 4 seater airplanes.  Nope: walk, snap a photo, leave.  Except for this jumping business.  It’s not just a little spray, or slight gob.  It’s ‘ an estimated 10 billion gallons‘ pouring out in three days.  Calculated into CFS (cubic feet per second), the typical way river flow is measured, this is about 5,000 cfs — the Colorado, down river from the Glenn Canyon dam.  Not terrifying, unless impeded by boulders, or buildings in downtown Juneau.

And it is happening enough, and strongly enough, (here and here) that the city fathers can smell terror coming on.

This summer, glacier-monitoring intensified. A pressure transducer to gauge water buildup, partly paid for by the city, was installed in a deep crack on the edge of the basin, with a satellite link sending back real-time data about the glacier’s hidden waterworks. A time-lapse camera was also positioned at the main pooling site for the first time to track bulges in the ice that could suggest dammed-up water.

No word yet from Alaska’s former governor whether she thinks this is due to a) the Russians, B) Climate Change or C) Liberal News Media.  She might do a write in option D) It’s Not Happening, because people wading through 3 feet of water is proof of nothing….

 

Mendenhall Glacier: Then (1894) and Now (2008)

Mendenhall Glacier: Then (1894) and Now (2008)

 

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