Decades of rising temperatures in the hills around the arctic hamlet of Fort McPherson in Canada culminated in two hours of catastrophic flooding as an unnamed lake burst through it’s melting embankment. It sent thousands of gallons of water in the valleys below. It caused a slow slide of mud and debris that engulfed over a mile of landscape. No one was hurt.
This part of the world is covered in permafrost, a thick subsurface layer of soil that remains frozen throughout the year, occurring mainly in polar regions.This ice was deposited tens of thousands of years ago during the retreat of the Laurentide Ice Sheet. In recent decades, warmer weather and heavier rains have accelerated thaws that mark the landscape. This whole process is known as a permafrost thaw slump. It begins when rain and heat melt headwall ice, exposing previously frozen soil and sediment that is in turn washed away to uncover more ice. This over decades can eat away entire hillsides.
For WeatherNation: Meteorologist, Mike Witcher