The Southeastern and Midwestern portions of the United States experienced historic tornado activity in the spring of 2011. During the week of April 18-22, 2011, the meteorological community began to discuss a potentially significant severe weather scenario developing in forecasted model runs for the following week. Several telling meteorological parameters foreshadowed the historical tornado activity that was to follow. The tornado outbreak that ensued resulted in April being ranked the country's most active tornado month on record, with 753 tornadoes. The previous record had been set in April 1974, with 267 tornadoes. From April 25 to 28, 2011 hundreds of tornadoes touched down from Texas to New York, with some of the strongest and most devastating on April 27 occurring in Alabama, Mississippi, Georgia, and Tennessee. According to the National Weather Service (NWS), tornado-caused deaths reached 364 during the month of April, with 321 people killed during the April 25-28 tornado outbreak. Less than a month later, on May 22, more than 50 tornadoes touched down across an eight-State area, the most powerful of which was a 0.75-mile-wide tornado that cut a 6-mile path through Joplin, MO. The tornado destroyed thousands of homes and caused widespread damage in the city. This historic tornado resulted in 161 fatalities, the most fatalities ever recorded from a single tornado since modern record keeping began in 1950. While tragic, major catastrophic events and disasters such as the tornadoes of spring 2011 often afford unique opportunities to research how hazards affect the built environment. The maximum winds associated with many of the tornadoes were well above the wind speeds used to design and construct many of the buildings damaged and destroyed during the tornadoes, so significant damage to the built environment would be expected. However, important information can be garnered related to building performance and tornado sheltering after such an event. Damage assessments can also be used to measure the effectiveness of adopted building codes, standards, and practices, and to assess how buildings built to design-level or near design-level respond near the edge of violent tornadoes or along the path of weaker tornadoes. The Federal Insurance and Mitigation Administration (FIMA) of the U.S. Department of Homeland Security (DHS) is responsible for investigating the effect of such events on the built environment. In response to a request for technical support from the FEMA Regional offices in the impacted states, FEMA deployed a Mitigation Assessment Team (MAT) to investigate the damage and provide technical assistance to the affected communities through their Joint Field Offices established in response to the events. The purpose of the MAT deployment was to assess the performance of buildings, infrastructure, and safe rooms, storm shelters, hardened areas, and tornado refuge areas affected by the tornadoes. The MAT was first sent to Alabama, Mississippi, Georgia, and Tennessee on May 6, 2011 and then re-deployed to Missouri on June 1, 2011. The MAT included FEMA Headquarters and Regional Office engineers, scientists, and communication specialists; representatives from academia; and practicing architects, engineers, and building experts from the design and construction industry. The MAT investigated the performance of residential buildings, commercial and industrial buildings, critical and essential facilities, and infrastructure, as well as safe rooms, storm shelters, hardened areas, and tornado refuge areas. Additionally, the MAT rated building damage according to the Enhanced Fujita (EF) tornado scale to assess wind speeds exerted on the building. The MAT then developed conclusions and recommendations based on their assessments. This report presents the MAT's field observations, as well as subsequent conclusions and recommendations.The MAT then developed conclusions and recommendations based on their assessments. This report presents the MATa#39;s field observations, as well as subsequent conclusions and recommendations.
|Title||:||Spring 2011 Tornadoes|
|Author||:||Mitigation Assessment Team (United States. Federal Emergency Management Agency), United States. National Oceanic and Atmospheric Administration, Texas Tech University. Wind Science & Engineering Research Center, University of Alabama, Simpson Strong-Tie (Corporation)., International Code Council, Tilt-Up Concrete Association|