Service Assessment The Historic Tornadoes of April 2011 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Weather Service Silver Spring, Maryland Cover Photographs: Tornado tracks and damage pictures from eastern Mississippi, central and northern Alabama, and northern Georgia. Map: National Severe Storms Laboratory. Photos: NWS Birmingham, AL; NWS Huntsville, AL; NWS Peachtree City, GA; Richard Okulski; Kevin Scharfenberg; Gary Woodall ii Service Assessment The Historic Tornadoes of April 2011 December 2011 National Weather Service John L. Hayes, Assistant Administrator for Weather Services iii Table of Contents Page Preface……………………………………………………………………………….…..……… iv Service Assessment Team…………………………………………………………….………... viii Executive Summary……………………………………………………………………………… 1 1. Introduction ............................................................................................................................... 3 1.1. NWS Mission ................................................................................................................. 3 1.2. Purpose of Assessment Report ....................................................................................... 3 1.3. Methodology .................................................................................................................. 3 2. Summary of Tornadoes and Damages ...................................................................................... 5 3. Summary of Meteorological Conditions ................................................................................... 6 4. Facts, Findings, Recommendations, and Best Practices ......................................................... 10 4.1.1. Pre-Season Awareness Activities .................................................................... 10 4.1.2. Severe Weather Awareness Weeks .................................................................. 10 4.1.3. Media Outreach ............................................................................................... 10 4.1.4. SKYWARN Spotter Training ....................................................................... 10 4.1.5. StormReady Program .................................................................................... 11 4.1.6. Emergency Management ................................................................................ 11 4.1.7. School Administrators ..................................................................................... 11 4.1.8. Adopt-a-County .............................................................................................. 12 4.1.9. Emergency Management Web Briefing Pages ................................................ 12 4.2. Situational Awareness of WFOs ................................................................................... 12 4.3. Internal WFO Operations and Planning ....................................................................... 13 4.4. Key Operational Systems ............................................................................................. 14 4.4.1. Weather Surveillance Radar - 1988 Doppler (WSR-88D) .............................. 14 4.4.2. Backup Operations .......................................................................................... 15 4.4.3. AWIPS ............................................................................................................ 15 4.4.4. NWR ............................................................................................................... 16 4.5. WFO Tornado Products and Services .......................................................................... 17 4.6. Products and Services by SPC ..................................................................................... 20 4.7. Decision Support and External Communication .......................................................... 22 4.7.1. Pre-Warning Services ...................................................................................... 22 4.7.2. Webinars.......................................................................................................... 23 4.7.3. Web Graphics .................................................................................................. 24 4.7.4. Multimedia Web Briefings .............................................................................. 25 4.7.5. NWSChat ........................................................................................................ 25 4.7.6. Direct Contacts and Emails ............................................................................. 26 4.7.7. Standard Warning Products ............................................................................. 26 4.7.8. Interactive NWS (iNWS) ................................................................................ 26 4.8. Dissemination ............................................................................................................... 26 4.9. Social Media................................................................................................................. 27 4.10. Operations and Responses of External Partners .......................................................... 28 4.10.1. Emergency Managers ...................................................................................... 28 v 4.10.2. School Officials ............................................................................................... 29 4.10.3. Media .............................................................................................................. 29 4.11. Societal Impacts and Public Response ......................................................................... 29 4.11.1. Receiving Warning Information ...................................................................... 29 4.11.1.1. Importance of Multiple Warning Sources ...................................... 29 4.11.1.2. Varied Access to Dissemination Sources ........................................ 30 4.11.2. Message Comprehension ................................................................................ 30 4.11.2.1. Unclear Communication of Increased Certainty and Intensity ...... 31 4.11.2.2. Varying Siren Policies .................................................................... 31 4.11.2.3. Language Barriers .......................................................................... 32 4.11.2.4. Multiple Tornadoes ......................................................................... 32 4.11.3. Confirmation ................................................................................................... 32 4.11.3.1. Difficulties with Visual Confirmation ............................................ 32 4.11.4. Personalization ................................................................................................ 33 4.11.4.1. Communicating Geographic Specificity ........................................ 33 4.11.4.2. The False Alarm Effect ................................................................... 33 4.11.4.3. Altering Behavior ........................................................................... 34 4.11.4.4. Weather Myths as a Barrier to Personalizing the Threat ................ 35 4.11.5. Risk Reduction and Protective Action Behavior ............................................ 35 4.11.5.1. Unclear Communication of Protective Action Options .................. 35 4.11.5.2. Lack of Availability of Shelters and Safe Rooms ........................... 36 4.11.5.3. Lack of Awareness of Public Shelter Options ................................ 37 4.11.6. Public Response Summary ............................................................................. 37 4.12. Post-Event Activities and Support ............................................................................... 38 4.12.1. WFO Staff ....................................................................................................... 38 4.12.2. Southern Region Operations Center ............................................................... 39 4.12.3. Mapping of Tornado Tracks ............................................................................ 39 4.12.4. Damage Surveys ............................................................................................. 41 4.12.5. Post-Event Agency Coordination .................................................................... 42 5. Success Stories Resulting from NWS Products/Services ....................................................... 43 Appendices Acroynms……………………………………………………………………….………..…… A-1 Findings, Recommendations, and Best Practices………………………………..……………. B-1 Social Science Methodology and Response Model…………………………………………... C-1 April 22, 2011, St. Louis Metropolitan Area Tornado Event……………………………….… D-1 NWS Eastern Region Event Review NC/SC/VA U.S. Tornado Outbreak……………….…… E-1 vi Figures Figure 1: Tornado tracks from the April 27, 2011, tornado outbreak. Tornado reports are from 12 a.m. April 27 through 12 a.m. April 28. ................................................... 5 Figure 2: Radar images of early morning storm complex: left, Jackson, MS; right, Birmingham, AL, 4:59 a.m. Central Daylight Time (CDT), April 27, 2011. .............. 6 Figure 3: Composite weather analysis for 1200 Coordinated Universal Time (UTC) (7 a.m. CDT), April 27, 2011 (courtesy of Greg Carbin, SPC) .................................. 7 Figure 4: Radar mosaic from 1130 UTC (6:30 a.m. CDT), April 27, 2011 ............................... 8 Figure 5: Shown is infrared satellite image