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FIGURE 13. - Debris-mudfiow blocking Hogback Road about 1 mile north of Morrison on west side of Dakota hog- back. Photograph by Eugene R. Hampton, May 7, 1973. pound in that they failed along multiple slip surfaces. Many of them, moreover, passed down- slope into earthflows where the material tended to break up and disintegrate from wetting and flowage. This is the material that moved out onto the highways during the storm. Many small slumps and earthflows appeared along the outcrop of the Morrison Formation on the west side of the Dakota hogback, particu- larly at roadcuts where the natural slope had been oversteepened. Most of these small land- slides were very wet and soupy, and they passed downslope into debris-mudflows (fig, 13). In some places removal of material from the road- ways during cleanup operations only caused more material to flow into place. Arresting of motion in such places is possible only when the entire mass is removed or when the material finally dries out enough for flowage to stop. The flanks of both North and South Table Mountain have had a long history of landslid- ing (Van Horn, 1954, 1972; Gardner and oth- ers, 1971; Simpson, 1973). West 32d Avenue was closed temporarily when many new slumps appeared on the north flank of South Table Mountain after the May 5-6 rains, Some older slumps were reactivated or accelerated, includ- ing the large landslide just south of Rolling Hills Country Club. Two long-active landslides above Clear Creek, one at West 32d A venue and one at West 44th A venue (old Colorado High- way 58) were both in motion before the rains started (fig. 14), Their prior activity had been promoted by the prolonged wet weather earlier in the season. Both showed evidence of increased movement after the May 5-6 storm. Because of the heavy moisture take-up by the Highway 58 slide, the damage potential of con- tinued movement had been very large, involving an imminent threat to new Colorado Highway 14