The National Weather Service in Little Rock has shared some conclusions reached by meteorologist and structural engineer, Tim Marshall. Tim was on the Fujita Scale Enhancement Project team that developed the “EF Scale” for rating tornadoes; and he is frequently called upon to inspect high-end tornado damage.
After reviewing some of the damage and talking with NWS officials, Tim agreed EF4 damage occurred on the night of April 27, 2014.
Some have questioned whether or not EF5 damage occurred, NWS Little Rock found that many of the homes swept down to the foundation lacked anchor bolts securing the frame to the foundation. Additionally, damage to the school (pictured) resembles damage caused by EF4 winds or 160-190mph.
Why even bother with the rating? We all know it was bad, right? Understanding the magnitude of the winds and how the structures withstood or failed is important to designing new structures capable of surviving the storm. Violent Tornadoes (EF4 or EF5) make up less than 2% of all tornadoes that occur. In the United States, there many only be 3 or 4 occurences annually. Knowledge gained from understanding how structures stood up to the tornado is used to bolster building codes and design new buildings better suited to stand up to the winds.
Tim Marshall also reviewed damage from Hurricane Katrina, Joplin, MO, & Moore, OK. He serves on NOAA’s Quick Response Team and is employed with Haag Engineering which specializes in forensic engineering to understand how and why structures have failed.