Sunday, February 8, 2015

Precipitation

Precipitation in Utah varies greatly, from an average of a little less than five inches over the Great Salt Lake Desert to more than 60 inches at the top of the northern Wasatch Mountains. The average annual precipitation in the major agricultural areas of the state generally ranges between 10 to 16 inches. As a result, irrigation is vital to the profitable production of most crops. It is fortunate that the major agricultural areas of the state are adjacent to the mountains. There is usually adequate irrigation water except during periods of severe drought. The areas of the state below an elevation of 4,000 feet (all in the southern portion of the state) generally receive less than 10 inches of moisture annually.
Utah's wettest water-year on record since 1895 occurred in 1994-1995, when the state as a whole recorded 16.67 inches of precipitation. (A water-year goes from October through September.) Other very wet water-years include: 1940-1941, 16.57 inches; 1981-1982, 16.38 inches; 1982-1983, 16.22 inches; 1972-1973, 15.66 inches; and 1908-1909, 15.29 inches.
Utah's most severe winter since 1899 occurred during the 1948-1949 winter season. It was the coldest winter on record, and an accumulation of 78 inches of snow was reported at the Salt Lake City Airport during the season. This accumulation was 18 inches greater than the previous record of 1936-1937. Nearly a 25% loss in some livestock herds was reported, tourist trade reached an all-time low, and 10 people died from exposure, snowslides and other direct effects of the weather.
Utah's driest period since 1899 was recorded during 1976. In that year, the average precipitation over the state was 7.70 inches, compared to a previous record low accumulation of 8.79 inches in 1966. The drought extended into 1977, causing disastrous consequences throughout the state, including the serious depletion of soil water and the loss of many perennial plants. Water rationing and emergency transportation of water occurred in many communities, and ski resorts, farming and other investments that depend upon good snowcover were financially strapped.
Click here for a color map showing the Annual Normal Precipitation for Utah (published in 1996).
Click here for a color map showing the Average Annual Snowfall for Utah (published in 1996).
Click here for more information on Utah's driest and wettest periods.
Much of the information for this section originally appeared in the copyrighted book Utah's Weather and Climate, edited by Dan Pope and Clayton Brough, in 1996. UCCW Directors have received permission from the copyright owners of this book to reproduce such information on its website and to revise and updated it where appropriate.

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