Response to Flash Flood Warnings: State of our Knowledge

1. Response to Flash Flood Warnings: State of our Knowledge Burrell E. Montz Department of Geography East Carolina University montzb@ecu.edu

2. Topics • Short fuse events • Flash floods • Tornadoes • Overview of studies • Summary of findings • So what...?

3. The Problem There remains, then, the need for a mathematicalmodel of human response to warnings, a model that wouldmimic all essential characteristics of human response in asetting of a local flood warning system and that would enableone to predict the outcomes of decision-event pairs. Krzysztofowicz, R., 1993 Reality

4. Components of Public Response • Hear • Understand • Believe • Personalize • Decide to act • Respond

5. What People Say Gruntfest et al., 2008

7. What People Do League, 2008

9. Actual versus Anticipated Behavior • Difference between what people say and what they do • Importance of context and circumstance • Difficult to document impacts of • Time • Memory • Cognitive dissonance

10. Tornado Studies: Sources of Information Schmidlin et al., 2009; Schmidlin and King, 1997; Balluz et al., 2000

11. Actions and Reasons:35% took shelter • Positive actions correlated with • Perceived danger • Presence of children • High school education • Hearing warning • Having a basement • Being married • Negative actions correlated with • Previous damage • Less education • God’s will • Lack of access to shelter • Limited mobility • No correlation • Age, gender, race • Lead time • Owning NWR • Family size • Previous experience

12. NWS Service Assessments • Super Tuesday 2008 Tornadoes • 57 dead • 18 (32%) heard some warnings • 11 (61%) heeded warnings • 8 (44%) sought shelter • 6 (33%) did not • Mothers’ Day 2008 Tornadoes • 21 dead • 11 (52%) knew of warning • 10 (47.6%) tried to take shelter ________________________ • 14 groups interviewed • 6 (42.8%) heard official warning • 6 heard from family or friends • 4 (28.5%) sought shelter • 6 tried but it “came too fast”

13. Flood Fatalities Source: League, 2009, http://www.geo.txstate.edu/lovell/IFFL/research.html

14. Vehicle Deaths Source: League, 2009, http://www.geo.txstate.edu/lovell/IFFL/research.html

15. Gender Breakdown* * Where reported Source: League, 2009, http://www.geo.txstate.edu/lovell/IFFL/research.html

16. So what about warnings?

18. But... • There is a difference between • Intentional Drivers • Situational Drivers League, 2009

19. False Alarms, Near Misses, and Response • What we know • Very different definitions of false alarms • NWS vs public • Perceptions of accuracy vary • NWS vs public • Cry wolf or warning fatigue or neither • Influence of event type • We don’t know enough Barnes et al., 2007

20. And... • There is no ONE public • Different languages • Different understandings • Different situations • Different capabilities • Different needs

21. Long way to go...

22. Conclusion • NWS mission: Protect life and property • NWS warnings are only the beginning of meeting this mission • Warnings move through various paths to the public • Warnings are received and understood differently • Collaborative effort required to get positive, protective responses • Social science research required to understand why people respond the way they do under what circumstances

23. Thank youAny questions you’d like to wade through? http://blogs.davenportlibrary.com/sc/wp-content/uploads/2008/04/no-wading.jpg