Climate of Salt Lake City - Other Weather Events

Other Weather Events

The phenomena El Niño and La Niña also affect precipitation along the Great Basin, bringing occasional cycles of drought and flooding. The largest recent flood in Salt Lake City occurred in 1983. Triggered by a powerful El Niño, an exceptionally large snowpack caused flooding and massive damage. City Creek burst from its underground diversion and flooded the city. Some streets, such as State Street and 1300 South, were diverted into makeshift rivers to accommodate the overflowing creek. Some flooding also occurred in 1987, when the Great Salt Lake reached its all-time maximum water level.

One of the most significant weather events in Salt Lake City occurs in mid-winter, when temperature inversions sometimes form, resulting in cold and extremely foggy, hazy weather in the city while the surrounding mountains enjoy warmer temperatures and sunshine. Temperature inversions are extremely unhealthy and can occur weeks at a time, and are most pronounced in the heart of winter, although may occur in other seasons to a lesser extent. Humidity is only high enough and temperatures cold enough for fog to occur in the heart of winter, although haze and smog can be found year-round. Inversions occur when strong areas of high pressure park themselves over the Great Basin. It usually takes a cold front to force out or break down the high pressure. Consequently, inversions are very rare in spring and fall, when the atmosphere usually takes on a progressive pattern, with fronts moving through frequently.

Tornadoes are also relatively uncommon. However, there has been at least one damaging tornado in the city. The Salt Lake City Tornado of August 11, 1999, which killed one person and injured 60, resulted in only the second ever fatality from a tornado in Utah, and caused about $500 million in damage. As a result of extended drought patterns, Salt Lake City constructed several reservoirs to hold excess water during flood periods and provide water during drought conditions. Additionally, artesian wells and water siphoned from Utah Lake miles to the south act as alternate water sources for the city.