U.S.+Heat+Wave+(1988)

A heat wave is defined as "when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 degrees C (9 degrees F)", according to the World Meteorological Association. The heat wave of 1988 in North America was one of the most severe in history, and left most of the central United States in complete dryness. In the late winter, the drought started, and conditions deteriorated throughout the spring. Then in the summer, many locations began to receive less and less precipitation, and the weather worsened. The drought began along the West Coast of North America in `86 and `87, and extended to the northwestern area of the United States towards the end of 1987. In 1988, the drought intensified over the Great Plains and spread to the eastern region of the United States as well. The conditions continued through 1989 and 1990, although it was not considered a drought because luckily, normal rainfall returned to much of the United States. As seen in Figure 1, throughout the three years that it was prevalent (1987- 1989), the brutal conditions associated with the drought traveled throughout the United States and affected many different areas. The record high temperatures and the lack of precipitation led to very significant effects around the continent.

**Meteorological Causes:** A typical heat wave occurs when high pressure aloft strengthens and remains that way for several days. However, this particular heat wave was developed in many different places at a different time, so the exact meteorological cause in a regional area is not clear. Since 1988, scientists have studied the drought in great detail, particularly the odd conditions that the cold surface temperature anomaly caused. This is possibly one of the main causes of the heat wave in 1988, and it may be an underlying cause of all droughts. One of the main factors that would explain the cold temperature anomaly, according to NASA, is the uncommonly strong intensity of the Pacific La Nina in 1988. During normal La Nina years, a lower level jet stream is usually weakened, which causes precipitation in the central United States from the Gulf of Mexico. A large anti-cyclone, which is a high pressure zone, often forms over the Great Plains or the central United States, and air masses within the anti-cyclone tend to sink downward and diverge away from the center of the wind system (see Figure 2). This sinking of the air prevents clouds and precipitation from forming. Another common condition that occurs during La Nina is when the Intertropical Convergence Zone shifts north. Below average sea surface temperatures along the equator in the Pacific Ocean during the spring of 1988 and warmer than normal water from 10 to 20 degrees north latitude were other conditions of La Nina that shifted the ITCZ. The ITCZ pushes the trade winds that blow from east to west in the Tropics further northward.



The heat wave was said to be the worst since the Dust Bowl of the 1930's, and it caused much destruction and deteriorated the economy, living conditions, and rivers and lakes of the Great Plains and much of North America. Although the drought only covered 36% of the United States and the Bowl covered 70%, it is the costliest drought in United States history and the second most costly natural disasters to strike the United States. 30 states were affected, and a state of emergency was declared in 12 states. This catastrophic natural disaster exceeded the nationwide costs from Hurricane Andrew in 1992, the Mississippi River floods of 1993, and the San Francisco earthquake in 1988. The total cost of the almost three year drought was roughly $71 billion, $1.8 billion in western Canada alone. This enormous sum of money was mostly because of the major losses in energy, power, water, precious ecosystems, and agriculture, which was a main source of business and profit among people living in the states affected. In all, the drought killed 5,000 to 10,000 people, including heat stress-related deaths. The Mississippi River was reduced to just a trickle of water (Figure 3). Temperatures in Valentine, Nebraska, and Sioux Falls, South Dakota, reached 110 degrees, with readings that reached the highest of the century in many other places. The heat wave also caused extensive forest fires that burned across western North America, including the well known Yellowstone fire.
 * Effects: **

High temperatures: 93,94,98,101,99,99,96,91,90,91,92,93,103 Highest temperature on record in Pittsburg history- 103 degrees F (July 16, 1988)
 * Record Temperatures- 1988 **
 * Pittsburg recieved the longest heat wave ever recorded for the city from July 4-16, 1988.
 * The Twin Cities in Minnesota received a high temperature of 105 degrees on July 31, 1988.
 * Temperatures in Texas reached 100 degrees F on 29 consecutive days

Works Cited "Drought: A Paleo Perspective -- 20th Century Drought." //NCDC: * National Climatic Data Center (NCDC) *//. N.p., n.d. Web. 4 June 2012. 

"Droughts and Heat Waves — Infoplease.com." //Infoplease: Encyclopedia, Almanac, Atlas, Biographies, Dictionary, Thesaurus.// //Free online reference, research & homework help. — Infoplease.com//. N.p., n.d. Web. 4 June 2012. . Trenberth, Kevin. "Origins of the 1988 North American Drought ." Science. N.p., 23 Dec. 1988. Web. 21 May 2012. "weather.com - Storm Encyclopedia - ." National and Local Weather Forecast, Hurricane, Radar and Report. N.p., n.d. Web. 21 May2012.<http://www.weather.com/encyclopedia