National Weather Service Hazard Simplification: Public Survey Final Report Prepared for National Weather Service Silver Spring, MD Prepared by : Eastern Research Group, Lexington, MA June 1, 2018 Executive Summary ............................................................................................................... ES-1 Overview........................................................................................................................................ ES-1 Current Knowledge ........................................................................................................................ ES-3 Prototype Testing .......................................................................................................................... ES-4 Recommendations ......................................................................................................................... ES-8 1.0 Introduction and Overview ..............................................................................................1 2.0 Message Testing Approach ..............................................................................................4 2.1 Prototypes ............................................................................................................................... 4 2.2 Scenarios and Prompts ............................................................................................................ 5 2.3 Protective Response Questions ............................................................................................... 7 2.4 Current Knowledge .................................................................................................................. 8 2.5 Questionnaire Overview .......................................................................................................... 8 3.0 Statistical Sampling Approach .......................................................................................10 3.1 Geographic Areas .................................................................................................................. 11 3.2 Sample Sizes .......................................................................................................................... 11 3.3 Inclusion Criteria ................................................................................................................... 13 3.4 Mode ..................................................................................................................................... 14 3.5 Time Frames and Final Sample Sizes ...................................................................................... 14 4.0 Statistical Analysis Approach .........................................................................................15 4.1 Outcome Variables and Treatments ...................................................................................... 15 4.2 Ordered Logistic Regression .................................................................................................. 15 4.3 Other Explanatory Factors ..................................................................................................... 17 5.0 Winter Weather: Mild Regions ......................................................................................19 5.1 Basic Demographics ............................................................................................................... 19 5.2 Current Knowledge ................................................................................................................ 20 5.3 Prototypes Analyses .............................................................................................................. 21 5.4 Summary and Conclusions ..................................................................................................... 31 6.0 Winter Weather: Cold Regions.......................................................................................33 6.1 Basic Demographics ............................................................................................................... 33 Hazard Simplification Public Survey – Final Report i 6.2 Current Knowledge ................................................................................................................ 34 6.3 Prototypes Analyses .............................................................................................................. 35 6.4 Summary and Conclusions ..................................................................................................... 45 7.0 Thunderstorms ...............................................................................................................47 7.1 Basic Demographics ............................................................................................................... 47 7.2 Current Knowledge ................................................................................................................ 49 7.3 Prototypes Analyses .............................................................................................................. 50 7.4 Summary and Conclusions ..................................................................................................... 60 8.0 Tornadoes ......................................................................................................................62 8.1 Basic Demographics ............................................................................................................... 62 8.2 Current Knowledge ................................................................................................................ 63 8.3 Prototypes Analyses .............................................................................................................. 64 8.4 Summary and Conclusions ..................................................................................................... 68 9.0 Coastal Flooding ............................................................................................................70 9.1 Basic Demographics ............................................................................................................... 70 9.2 Current Knowledge ................................................................................................................ 71 9.3 Prototypes Analyses .............................................................................................................. 72 9.4 Summary and Conclusions ..................................................................................................... 79 10.0 Flash Flooding ................................................................................................................81 10.1 Basic Demographics ............................................................................................................... 81 10.2 Current Knowledge ................................................................................................................ 82 10.3 Prototypes Analyses .............................................................................................................. 83 10.4 Summary and Conclusions ..................................................................................................... 90 11.0 Areal Flooding ................................................................................................................92 11.1 Basic Demographics ............................................................................................................... 92 11.2 Current Knowledge ................................................................................................................ 94 11.3 Prototypes Analyses .............................................................................................................. 95 11.4 Summary and Conclusions ................................................................................................... 105 12.0 Conclusions and Recommendations ............................................................................. 107 12.1 Current Knowledge .............................................................................................................. 107 Hazard Simplification Public Survey – Final Report ii 12.2 Overall Results by Prototype and Hazard ............................................................................ 107 12.3 Overall Results by Prompt Level .......................................................................................... 110 12.4 Overall Results by Protective Response ............................................................................... 110 12.5 Overall Results by Cross-Tabulated Prompt Levels and Protective Responses .................... 111 12.6 Recommendations............................................................................................................... 113 2. Part I - Key Demographics ...................................................................................................2 3. Part II - General Risk and Weather Questions .....................................................................3 4. Part III – Current Knowledge ...............................................................................................6 5. ................................................................................................................................................6 6. Part IV – Prototype Testing .................................................................................................7 7. Part