In addition to their variable rheology, lahars vary considerably in magnitude. The Osceola Lahar produced by Mount Rainier (Washington) some 5600 years ago resulted in a wall of mud deep in the White River canyon, which covered an area of over , for a total volume of . A lahar of sufficient size and intensity can erase virtually any structure in its path, and is capable of carving its own pathway, making the prediction of its course difficult. Conversely, a lahar quickly loses force when it leaves the channel of its flow: even frail huts may remain standing, while at the same time being buried to the roof line in mud. A lahar's viscosity decreases with time, and can be further thinned by rain, but it nevertheless solidifies quickly when coming to a stop.