Record-sized forest fires during the summer of 2002 in Arizona and Colorado were directly related to the extremely dry conditions. showing exposed channel of the Colorado and Dirty Devil Rivers, which are normally flooded by the lake, as well as the deltaic sediments that are deposited at the upper end of the lake; view to the east in October 2002. Under normal precipitation conditions, Utah receives less precipitation than every other state except Nevada.Average annual precipitation at Salt Lake City is about 16.5 inches, and precipitation statewide ranges from about 5 inches on the Great Salt Lake Desert to about 60 inches in the highest mountains (Butler and Marsell, 1972).The snowpack, and therefore the relative amount of water available for runoff, was about 78 percent of average in northern Utah drainages and ranged from 24 percent to 54 percent of average in the southern part of the State.In eastern and southeastern Utah, the end-of-season snowpack was the lowest since 19 (Natural Resources Conservation Service, 2002).The percentage of average flow for the eight index sites for 1999-2002 is shown in table 2.In 1999, streamflow was near or below average for the Colorado River, Beaver River, and Virgin River.Runoff from greater-than-normal precipitation since Sept. 1982 increased lake level to 101-year record of 5.46 feet above compromise level on June 15, 1984. Partially a result of large El Niño event of 1983-84. A hydrologic drought is defined as “a period of below average water content in streams, reservoirs, ground-water aquifers, lakes and soils” (Yevjevich and others, 1977).The relation of annual streamflow to average annual streamflow for the period of record for the eight index sites (fig.
The end-of-season snowpack, as measured by the Natural Resources Conservation Service SNOTEL system on April 1, 2002, was below average statewide.Utah’s weather is prone to extremes—from severe flooding to multiyear droughts.Five major floods occurred during 1952, 1965, 1966, 1983, and 1984, and six multiyear droughts occurred during 1896-1905, 1930-36, 1953-65, 1974-78 (U. Geological Survey, 1991), and more recently during 1988--2002.These streamflow-gaging stations are all located in southern Utah.By 2000, all of the index sites indicated below-average flow.Prior to current drought conditions, Utah experienced drought on a regional scale most recently in the late 1980s to early 1990s.