Warming leading to crumbling This image is a satellite photo of a monstrous landslide that occurred

Warming leading to crumblingThis image is a satellite photo of a monstrous landslide that occurred in Alaska in 2015. This site is a valley called the Taan Fjord within Glacier Bay National Park, and the glacier you see holding part of the slide volume is called the Tyndall Glacier. No one was in the area to witness this slide, but it’s a good thing there wasn’t, as they probably would have died. This slide was the largest non-volcanic landslide humans have seen in recorded history and it set off a tsunami that stripped trees off of the lower 200 meters of a slope farther down the valley.This is just one of a large series of slides examined as part of a recent study led by a researcher at the US Geological Survey. Using images from the long-lived Landsat satellite series, a record of Earth’s surface going back nearly 40 years, they picked a few time slices and investigated how many landslides Alaska had seen and how big they were. Their results suggest that the Tyndall Glacier slide probably won’t be the last of these monsters.Starting in 2012 there has been a dramatic increase of large landslides in this portion of Alaska, with the rate of slides more than doubling that seen any other time in the last 30 years. There are more of these slides, and they are also growing larger.This surge in landslides is hypothesized to be occurring because the area is warming rapidly. These slides are mostly occurring in the Spring and on slopes that are particularly susceptible to warming due to their exposure to the sun. Furthermore the average temperature in Glacier Bay during the year crossed 0°C in the year 2010, and for areas to stay permanently frozen they obviously need average temperatures below that number.The scientists hypothesize that the permafrost in this area is breaking down now that it is too warm. As the permafrost melts, the ice that was holding steep slopes together is gone and those slopes are crumbling. The areas that are collapsing first are the ones most prone to rapid warming – the ones that get the most sun in the spring. However, as temperatures continue to rise, these slopes are likely to keep crumbling, and even more will become susceptible to these large slides.-JBBImage credit: Digital Globe/Lamont Doherty Earth Observatoryhttps://www.ldeo.columbia.edu/news-events/detecting-landslides-few-seismic-wigglesReferences:https://link.springer.com/article/10.1007/s10346-017-0879-7http://glacierhub.org/2018/07/11/climate-change-behind-more-frequent-powerful-avalanches-in-alaska/http://blogs.ei.columbia.edu/2016/07/02/massive-landslide-detected-in-glacier-bays-fragile-mountains/https://blogs.agu.org/landslideblog/2016/01/02/tyndall-glacier-landslide-1/ -- source link

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