February 24 2015— Slow landslides in permafrost slide downhill on mountain slopes in the Brooks Range of Alaska. These massive frozen debris lobes are geohazards. They pose a potential threat to the Dalton Highway, Alaska’s lone road to the North Slope. There are 23 identified frozen debris lobes situated less than one mile uphill from […]
“Something chewed on the casing,” Margaret Darrow explained. “Probably a bear.” Blue chips were scattered from the cracked ABS pipe. Inside the casings that protect the holes drilled in and around frozen debris lobe -A there’s non-toxic propylene glycol. Propylene glycol, this brand a clear greenish liquid, prevents freezing – helpful for scientific instruments – […]
“It’s a very dynamic slope,” Margaret Darrow said, standing in front of frozen debris lobe -A. FDL-A is a slow landslide; among the frozen debris lobes documented it’s the closest to the Dalton Highway and the Trans-Alaska Pipeline. Although the lobes likely began their life as debris left over when Pleistocene glaciers disappeared 10 to […]
When the machinery mounted to the man-height pole announced “RTK initialized,” the scientists gave a cheer. It was late afternoon and the morning’s downpour had finally cleared. They were gathered in a sunny spot discussing what was still on the agenda for the day when the rover – the pole and its paramount differential GPS […]
We’ve joined scientists atop a frozen debris lobe, a slow-moving landslide in permafrost. They say we’re ‘on the back of the beast’. In the heavy rain and among fog-shrouded mountains, the scientists are making these uphill treks to record how temperature, water pressure, and local geological properties determine the slope movement of the massive lobes. […]
Less than one mile upslope from Alaska’s Dalton Highway, there are 23 frozen debris lobes looming. Frozen debris lobes (FDLs) are something like a cross between a landslide and a glacier. They’re silty sand and gravel, stones, icy frozen soil as well as liquid water kept from freezing by the intense pressure of the slow-motion push downhill. […]