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.,. 19 - (1) With torrential or "cloUdburst" type rainstorm, either area- wide or only in the steep upper reaches of the watershed, rapid water runoff occurs, generally accompanied by debris avalanching on the upper slopes. The water and debris attain high velocities and tend to become somewhat channeled, incorporating the coarse lag deposits which accumulate at very steep angles of repose in the steep intermittent stream beds of the lower parts of the high slopes. (2)' The mixing of storm, runoff, soil, and rock debris forms a viscous slurry of the approximate consistency of wet concrete mix. When these mud avalanches reach the level of the mudf10w fan, they generally become more definitely channeled, and follow one of the dis- tributary channels across the steep part of the fan. A rather high velocity is maintained by the channeling effect, the steep gradient, and the pressure of the moving mass from above and behind. When this stream of mud reaches the lower slopes, it spreads out, loses velocity, deposits much of its coarse load, and may be in part discharged into the Crystal River. Some Hydrologic and Engineering G~ology Implications of Mud Floods (1) One of the factors to b~ considered is the high kinetic energy of the v~ry dense and high velocity stream of mud and/or flood water. ,This gives it the tremendous capacity for erosion, deposition and de- struction that are earmarks of alpine mudflows. It should also be noted that the regime of these oCcasional mudflows has no particular relationship to the normal stream flow, and any control measures must take this into account. Debris samples taken from the well-observed Wrightwood, California mudflows of 1941 had a bulk density of 2.4 and