On April 3, 1974 the early morning weather map depicted a strong low pressure system in central Kansas with a cold front trailing south into eastern Texas. and a warm front extending east from the cold front through Arkansas Tennessee, and North Carolina. South of the front warm, humid Gulf air was in place. A line of early morning thunderstorms were moving through eastern Missouri and western Illinois. Northwest of the low pressure center snow was falling in western Kansas, eastern Colorado, and southern Nebraska.
|Portion of surface weather map for 7:00 a.m. CDT, April 3, 1974|
Forecasters at the National Severe Storms Forecast Center (now the Storm Prediction Center) saw the potential for severe weather the day before and had notified Weather Services Offices to be ready. However, the extent and intensity of the severe weather was still uncertain. By the morning of April 3 the potential for severe weather was coming into better focus. The first Severe Thunderstorm Watch was issued at 8:27 a.m. CDT for the Ohio Valley, and over the next 19 hours 28 severe weather watches were issued covering almost the entire area from the Gulf of Mexico to the Canadian border and from the Mississippi River to the East Coast.
|Map of the tornado tracks for April 3-4, 1974|
prepared by Dr. Ted Fujita
The first tornado of the outbreak touched down in Morris, IL (Grundy County). It was a weak (F0) tornado that was on the ground for only a tenth of a mile. An hour later two more tornadoes touched down in central Illinois, quickly followed by more tornadoes in Illinois and Indiana. Storms spawned tornadoes throughout the afternoon and evening at a rapid pace. At one point a total of 15 tornadoes were on the ground at the same time, and meteorologists in Indiana placed the entire state under a tornado warning. This was the first and only time in U.S. history that an entire state was under a tornado warning.
|The F5 tornado as hit hit downtown Xenia, OH.|
Photo by Kitty Marchant
|Depiction of the upper level conditions (left) and surface conditions (righ)t at 7:00 p.m. CDT on April 3, 1974|
There is no way to thoroughly write about all that occurred on the 18 hour period in April 1974 in a blog post. It was a much-researched and documented event. You can easily spend many hours reading through the huge amount of information available on the 1974 Super Outbreak. The Super Outbreak led to significant changes in warning procedures for severe weather. Many communities that did not have outdoor warning sirens did so in the aftermath of the Super Outbreak. NOAA's Weather Radio network rapidly expanded in the wake of the Super Outbreak so that warnings could be quickly disseminated. It also helped spur the National Weather Service modernization program.
This short documentary on the Super Outbreak provides an overview of just what forecasters and the public were up against that day. This shows actual footage of tornadoes as they struck Xenia, Cincinnati, and Louisville, causing massive damage and numerous deaths. Includes discussion of advance tornado preparation and emergency coordination. Courtesy of the National Archives.
Here are some sources for further reading. Many of these include numerous photographs, news accounts, and first-hand accounts of the events of that day. Several of the NWS pages contain links to other data and information about the Super Outbreak
NOAA Natural Disaster Survey Report - December 1974
NWS Nashville, TN - April 3-4, 1974 Super Outbreak
NWS Louisville, KY - 40th Anniversary of the April 3, 1974 Super Outbreak
NWS Wilmington, OH - The Super Outbreak of April 3-4, 1974
NWS Huntsville, AL - Remembering the April 3-4, 1974, Tornado Outbreak
NWS Birmingham, AL - The April 3rd and 4th 1974 Tornado Outbreak in Alabama
NWS Lincoln, IL - April 3-4, 1974 "Super Outbreak" of Tornadoes: Impacts on Illinois
NWS Indianapolis, IN - April 3, 1974 Super Outbreak