58 seconds in Tucson, Arizona June 22, 1977 Photos copyright Jack Sheaffer Arizona Daily Star Summer WAS*IS Wednesday

False Alarms: Warning Project Research Findings & Warning Accuracy Conceptual Model Lindsey Barnes WAS*IS July 2006

False Alarm Conventional Wisdom Cry wolf effect- Aesop's fable of “The Boy who Cried Wolf” False alarm effect- “The credibility loss [of a warning system] due to a false alarm” (Breznitz 1984)

Other False Alarm Research Dow & Cutter (1998): Repeated Response to Hurricane Evacuation Orders Carsell (2001): Impacts of a False Alarm The January 29, 2000 Ventura, California Experience

False Alarm Research Questions What are public perceptions of false alarms? Is “cry wolf” concept accurate for flash flood warnings? How do demographic characteristics influence perceptions about false alarms?

Survey Questions 1.Realizing it’s difficult to predict flash floods, I would prefer more warnings even if it means there are more false alarms or close calls. 2.One or two false alarms or close calls would reduce my confidence in future warnings. 3.Officials are too sensitive to the possibility of flash flooding. Demographic characteristics

Flash Flood False Alarms

Denver vs. Austin “Realizing it’s difficult to predict flash floods, I prefer more warnings even if there are more false alarms or close calls” N= 922 Not significantly different

Denver by Gender: “Realizing it’s difficult to predict flash floods, I prefer more warnings even if there are more false alarms or close calls” N= 419 X² =.011, p <.05

Austin by Gender: “Realizing it’s difficult to predict flash floods, I prefer more warnings even if there are more false alarms or close calls” X² =4.150, p <.05

Denver by Age: “Realizing it’s difficult to predict flash floods, I prefer more warnings even if there are more false alarms or close calls ” N=400 X² =.005, p <.05

Denver vs. Austin “One or two false alarms would reduce my confidence in future warnings” N=917 Not significantly different

Denver by Gender: “One or two false alarms would reduce my confidence in future warnings” N=399 X² =.072, p <.1

Denver by Age: “One or two false alarms would reduce my confidence in future warnings” N=400 X2 =.025, p <.05

Denver vs. Austin: “Officials are too sensitive to the possibility of flash flooding” X² =4.533, p <.05 N= 906

Conclusions People would rather have more warnings with the possibility of a false alarm or close call False alarms may not reduce confidence in the warning process Officials are not viewed as too sensitive –Need to re-evaluate conventional wisdom

Conclusions (continued) Demographic characteristics do matter: Flash flooding –Gender: females may be more tolerant of false alarms (both cities) –Age: older people may be more tolerant of false alarms (Denver only) Tornadoes –Having a basement or interior room: People with a place to seek shelter are less likely to have confidence reduced by tornado false alarms

Limitations and Future Work Interpretation of questions Survey answers vs. actions How much can we generalize from these case studies?

Conceptual Model of Warning Accuracy Event followed warning as specified Event occurred but was less severe than warning Event occurred but was more severe than warning Warning was issued but event did not occur Warning was not issued but event occurred 1985 Hurricane Elena False Alarm Perfect Warning Unwarned Event Red River Flood Oklahoma Tornados Model developed by Lindsey Barnes Plainfield Tornado 1996 Hurricanes Fran and Bertha Near-miss Evacuations

Questions for WAS*ISers What are the most successful ways to implement this social science research? –Policy? –Introduction of new performance measures? –Public education? How can this information be useful to practitioners? Other examples for model?

Lindsey Barnes Public Perceptions of Flash Flood False Alarms

Austin Demographic Variable Chi-square value P valueDemographic Variable Chi-square value P value FLASH FLOODING Realizing it’s difficult to predict flash floods, I prefer more warnings even if there are more false alarms or close calls Gender Gender Age Age Education Education Income Income Flood experience Flood experience Have tornado plan One or two false alarms would reduce my confidence in future warnings Gender Gender Age Age Education Education Income Income Flood experience Flood experience Have tornado plan Officials are too sensitive to the possibility of flash flooding Gender Gender Age Age Education Education Income Income Flood experience Flood experience Have tornado plan AustinDenver Red p<.05 Blue p<.1

TORNADOES Demographic VariableChi-square valueP value Realizing it’s difficult to predict the exact location of tornadoes, I prefer more warnings even if there are more false alarms or close calls Gender Age Education Income Have basement Have tornado plan One or two tornado false alarms would reduce my confidence in future warnings Gender Age Education Income Have basement Have tornado plan Officials are too sensitive to the possibility of tornadoes Gender Age Education Income Have basement Have tornado plan Red p<.05 Blue p<.1 Austin- only