As many as two dozen people were killed on Saturday, March 22, 2014 when a massive landslide swept down a rain-soaked hill near Oso, Washington. NASA satellite imagery taken before and after the event shows the extent of the event.

Using the ‘sliders’ on the image below you can compare how the area looks normally (left) versus how it looked after the landslide (right).

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[wpw_ba_img src=”http://lh6.googleusercontent.com/-I2mSOZBkFnQ/UzMQFKXi74I/AAAAAAAAB0s/tcA9N10o6cY/s600/wa-before.jpg” data_second=”http://lh5.googleusercontent.com/-VXmVfoDsFqQ/UzMQFPSNLNI/AAAAAAAAB0w/kIX2gla6sTA/s600/wa-after.jpg” title=”Satellite imagery comparison of the area near Oso, Washington before and after the March 22, 2014 landslide. (NASA EO)” data_info=”Satellite imagery comparison of the area near Oso, Washington before and after the March 22, 2014 landslide. (NASA EO)”]
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From NASA:

On March 22, 2014, a rainfall-triggered landslide near Oso, Washington sent muddy debris spilling across the North Fork of the Stillaguamish River. The debris engulfed numerous homes, resulting in the deaths of at least 14 people. As of March 25, authorities reported that 176 people were still missing.

The slide left an earthen dam that blocked the river, causing a barrier lake to form. The Operational Land Imager (OLI) on Landsat 8 acquired this image of landslide debris and the barrier lake on March 23, 2014. An image of the same area acquired on January 18, 2014, is shown for comparison.

As water backed up, it raised fears of a potential flash flood. On March 23, water began to flow around the north side of the dam. However, as of the afternoon of March 25, a flash flooding watch issued by the National Weather Service remained in effect for parts of Snohomish county.

According to Durham University geologist Dave Petley, the landslide was a reactivation of an earlier landslide that caused problems in 1988 and 2006.