America's Youngest, Fastest-Growing Glacier May Be Short-Lived

Deep and out of sight within the crater of Mount St. Helens, a glacier begins to move.

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Jul 5 2015, 9:16pm

Image: USGS

Mount St. Helens is a bit of a wasteland. It's gray, barren—as alien as anywhere else on Earth. Its flanks are loose piles of decomposed volcanic rock and sandy scree. Climbers are advised to pack masks to protect against short-lived clouds of volcanic dust that may arise as the result of steam and ash plumes. Ascending the volcano, a nine mile round-trip with about 5,000 feet in elevation gain, feels like climbing it twice, as the looseness of the mountainside soaks up half of a climber's efforts: two steps up, one step back. Mount St. Helens locals often speak of the mountain—or the catastrophic 1980 eruption that left it in its current state—with legit bitterness, as if the eruption was the work of some corporation and not nature doing its thing.

Mount St. Helens does have one thing going for it: A newborn glacier that is actually growing. As glaciers recede all over the planet, deep within the folds of the volcano's hollowed-out crater and generally out of sight of visitors is the world's youngest glacier, Crater Glacier. Since its genesis following St. Helens' 1980 eruption, the glacier has advanced by as much as 135 feet per year, while adding thickness at a rate of up to 50 feet per year. Nonetheless, the growing ice sheet remained unknown to the public for 20 years and to geologists for nine. Even now it remains out of view of publicly-accessible climbing routes, as does much of the still-active crater, hidden beneath the lip of a precarious and potentially quite lethal cornice.

Seeing the glacier in person requires an expensive guided tour, the first of which will take place later this month. The tour's $200 pricetag has ignited its own eruption of sorts, as noted in a Seattle Times article published this week.

Image: J Brew/Flickr

Before Mount St. Helens erupted in 1980, an event that turned what was before a symmetric cone often likened to Mount Fuji into today's hollow-out crater, dropped the mountain's top elevation by some 1,400 feet. The event killed 57 people and leveled 230 square miles with pyroclastic flows while releasing some 1.5 million metric tons of sulfur dioxide into the atmosphere. 3,900,000 cubic yards of material poured into the Columbia River via volcanic mudflows. Eruptions continued from May of 1980 until the next winter, where temperatures on the crater floor dropped enough for snowfall to begin accumulating, along with rockfalls (the glacier is almost half rock) and avalanches. Its location at the bottom of the crater keeps the nascent glacier shielded from the Sun.

"Surface cracks suggest that the ice mass is beginning to move," notes the US Forest Service. "As the size of the ice mass increases it may begin to erode the lava dome it surrounds. Today, the snow and ice in the crater is equal in volume to all of the pre-eruption glaciers on Mount St. Helens combined."

The movement is very new, observed for the first time only two years ago. It adds a twist to the glacier's future development. The movement comes in some part as the result of a second-wave of volcanic activity that occurred in the mid-'00s, which formed a second lava dome within the crater that acts to push the glacier upward and outward. An initial concern was that the new activity would quickly melt the glacier with the result being a another wave of mudflows and catastrophic flooding. Fortunately, it turns out that Crater Glacier is quite well insulated.

That said, the summer of 2015 in the Pacific-Northwest has been exquisitely awful, with temperatures routinely touching 95 degrees and above. Shade can only protect the glacier so much. "I'm rooting for the glacier, myself," Steve Schilling, a USFS scientist, told the Seattle Times. "But I wouldn't be at all surprised to see it recede this year."

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