Mother Nature Network: Deadly mudslides can unfold in any of the 50 U.S. states, but a combination of geologic factors makes the West Coast especially vulnerable to the type of destructive flow that pummeled northwest Washington on Saturday (March 22), geologists say. Mudslides generally form when a massive layer of unconsolidated rock becomes waterlogged and slips under the force of gravity. The basic ingredients for a mudslide include large areas of unconsolidated rock, steep mountain slopes, and areas with shallow...