This Was One Of The Largest Landslides Ever, So How Did No One See It For Months?

How big is this landslide in China’s Tonzang valley? Big. So big that it created many (many!) new lakes. So big that, at just one of its three major points of origin, it shifted 395 million (million!) tonnes of earth. But it didn’t just happen — it actually occurred back in July. So why are we only seeing it now?

A landslide of this scale is almost always the result of an extremely powerful earthquake, but in this case it was actually a tropical storm that did it: Tropical Storm Komen, that moved through the area back in July. The continuing rains that drenched the area were so intense and so on-going that satellite imagery (the only imagery, at this point, even able to document the scale of the damage) hasn’t been able to peek through the cloud cover since those rains started in July.

The sky only recently cleared up enough that NASA’s satellites could peek through to see what was left and get the first look at the slide. After looking at the images, researchers believe that the massive landslide took place in just under three minutes, in which time it sent the earth around it flying at an incredible rate of 50m/s. Fortunately, the closest village was over 32km away from the site.

Images: NASA Earth Observatory images.