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Publications - Occasional Papers

Century of Struggle against Snow: A History of Avalanche Hazard in San Juan County, Colorado

INSTAAR Occasional Paper 18

1976, 97 pp. 11 plates. Copy reprinted from scan. (cost: $5)

An examination of historical data relating to avalanche activity in San Juan County was undertaken for the period 1875–1975. San Juan County was a booming gold- and silver-producing area, reaching its peak in population, mineral production, and, correspondingly, avalanche deaths and destruction to property during the period 1880 through World War I.

Data were obtained from newspapers of the period and by interviews. Avalanche sites were plotted on USGS 1:24,000 scale maps and tabulations of avalanche frequency were developed, chronologically and by geographic location. A total of 95 avalanche deaths were recorded during the survey period. Of these, 69 percent occurred while the victims were in fixed positions, either in or near a building. The remaining 31 percent of deaths occurred while the victims were traveling in the mountains. One hundred properties were damaged by avalanches; of these, 89 were hit between one and three times and 11 were hit four or more times. The location suffering the most damage was the Iowa­Tiger Mill in Arastra Gulch, 2.7 miles due east of Silverton. During a period of 23 years, it was hit on eight occasions, being almost totally destroyed twice. Fifteen geographic locations were plotted where deaths and/or burial from avalanches resulted.

The major avalanche disasters occurred during heavy storm periods, March 1884 and March 1906. During the storm of March 1906, 12 men were killed in the Shenandoah Mine boarding house above Cunningham Gulch, 4.4 miles southeast of Silverton, and six deaths were recorded elsewhere during the storm period. However, avalanche deaths and destruction also occurred during periods of light or no snowfall. After the storm of February 1891, when only 6 inches of new snow fell, one avalanche death was reported and three men were caught but escaped injury.

The avalanche hazard during this historical period was widespread and not concentrated in any particular area primarily because the mining operations were scattered throughout the county with diverse traffic routes. This represents a significant difference from the present-day pattern of avalanche hazard which is concentrated along highways 550 and 110 and within the town of Silverton.

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