Geological Survey Bulletin 1221-A Rockfalls and Avalanches from Little Tahoma Peak on Mount Rainier, Washington

Dust clouds frequently veiled the north face of Little Tahoma Peak during the winter, spring, and summer months of 1964. These clouds were caused by rocks bounding from the rockfall scar onto a long dusty apron of debris that bordered the scar base and reached onto Emmons Glacier. The rocks apparently were dislodged from the scar by freeze and thaw, by melt water from a hanging glacier perched on the east side of Little Tahoma Peak, and by wind currents. At times, winds would sweep the dust clouds upward and eastward, causing the surface of Fryingpan Glacier to become unusually dirty. Although rocks continued to fall from the scar during late August and early September, dust clouds became rare after this period because frequent rains and snows dampened the rockfall debris at the base of the cliff.

These dust clouds were small and insignificant in comparison with the great palls of dust that accompanied the avalanches. The effects of those clouds were still to be seen in July 1964 on the southern slope of Mount Ruth, where conifers were still mantled with nearly an inch of silt and fine sand that had settled out of the air. Much of this sand and silt had been washed off by rains before the following September.