Mount St. Helens, Washington

 Below shows Spirit Lake off to the left (you can just see a sliver of blue).  When the side of the mountain slid down the slope from the earthquake that happened, the lake was filled with trees and other debris causing it to rise by 200 feet.

 Picture of this popular mountain before the eruption.  It was a vacation destination for thousands, including a boy scout camp and many other campgrounds.

 Picture after the eruption.  Within 10 minutes, 230 square miles of forest was destroyed, mostly by the explosion but also by the heat and ash fall out.