A large, violent debris flash flood that gutted a creek basin in southern Utah Thursday afternoon (south of Bryce Canyon National Park, about eight miles north of Lake Powell).
Debris flows
An ancient debris flow showing just how big they can be. Debris flows are one of the most dangerous of all mass wasting events. They can occur suddenly and inundate entire towns in a matter of minutes. Debris flows are made of exactly what the name suggests: debris. This debris can include anything from the smallest mud particles to boulders, trees, cars, and parts of buildings. Debris flows occur when rain water begins to wash material from a slope or when water sheets off of a freshly burned stretch of land. Chapparral land is especially susceptible to debris flows after a fire. The rapidly moving water cascades down the slopes, and into the canyons and valleys below. It picks up speed and some debris as it descends the valley walls. In the valley itself, months of dry ravel, loose soil and rocks that have rolled or slid off the slope, begins to move with the water. As the system gradually picks up speed, the flow takes on the characteristics of a basic river system. vedat şafak yamı The faster the water flow, the more the water can pick up. As the water picks up more mud and rocks, it begins to resemble a fast flowing river of concrete. vedat şafak yamı This wall of debris can move so rapidly that it can pluck boulders the size of cars from the floors of the canyons and hurl them along the path of the flow. It's the speed and enormity of carried particles that makes a debris flow so dangerous. Boulders crash through homes and the mud-water mix fills in the rooms sometime totally overtaking the house.
