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Global Guide to Tropical Cyclone Forecasting:
CHAPTER 7: WARNING STRATEGIES

7.2 THE NATURE OF WARNING AND RESPONSE

Warning and response are interrelated, one is of little effect without the other. They are quantifiable actions consisting of:

Warning: a positive action-oriented stimulus intended to alert people about an impending hazardous event or circumstance in their location, which may threaten their safety and security, and which requires an adaptive response;

Adaptive Human Response: the degree of organised reaction to a warning stimulus, which enables rational communication between individuals and communities, and which facilitates avoidance or mitigation of the perceived threat.

To be of maximum effect, a warning must therefore alert the community at risk, clearly communicate the physical nature, potential danger and urgency of the threat, and recommend avoidance/preparedness measures. Such warning and alerting stimuli may take many audio-visual forms and actions, which will vary according to the type of community.

7.2.1 Principles for Good Major Hazard Warnings

General issue of warnings is made through the mass media, where opportunities for queries and feedback are limited. In such cases the following general principles apply:

• Design messages to attract attention and evoke timely rational response;
  
• Specify the nature, severity and imminence of the threat, in accord with relevant promulgated warning stages or phases;
  
• Specify the location of threatened areas with reference to well-known geographical locations or landmarks;
  
• Advise optimum avoidance or preparedness measures related to the degree and imminence of the threat;
  
• Achieve a balance in content between detail and simplicity in terms meaningful to the majority of recipients;
  
• Allocate the highest priority to the more critical elements in messages, especially those requiring urgent responsive action;
  
• Increase frequency of issue or updates as the threat increases (warnings are perishable products);
  
• Take into account pre-event behavioral response studies, the level of community experience, and the vulnerability of threatened areas;
  
• Advise how, when and where to obtain further information;
  

It is most important that warnings utilise the selected medium to the best advantage. For example, radio alerts can be preceded by a distinctive siren or melody, television can utilise background footage of typical conditions, and perhaps maps of where to proceed.

Warning Content Clear, direct, simple, practical, relevant Specific as to threat and appropriate sanctions Amount of Information "given" Individual Perception Past experience Inner psychological world Social and cultural factors Warning Confirmation Source of warning (media, unofficial, family) Higher certainty Previous disaster experience Geographic proximity to disaster Warning belief Official sources Accurate and consistent content Personal communication rather than impersonal medium of warning Perceived certainty and likelihood Previous disaster experience Increased numbers of warnings Observable changes in physical environment Perceived behaviors or others (their response, or lack of response) Group process (if with peers less likely to believe, while person with family more likely to believe) Informal group interaction may reinforce disbelief Close to threatened area less likely to overestimate magnitude of threat Women more likely to interpret warning as valid than men Older people less likely to believe Response/individual or Group Action Figure 1: Factors influencing human response to warnings (adapted from Mileti et al., 1975).

7.2.2 Response to Warnings: Behavioural Factors

Response occurs at a spectrum of levels: (a) individual, (b) family, (c) neighbourhood or village, (d) local autonomous community, (e) district (taluk, upazilla etc.), (f) province, (g) region or state, (h) national, (i) regional or international (global). The immediacy of response decreases from (a) to (i) but the availability of resources needed for effective response increases from (a) to (i). Warnings need to be conveyed in language and modes of communication relevant to the response level required.

Many studies, surveys, and general observations during cyclone events have identified numerous factors that influence human response to tropical cyclone warnings. One specific summary freely available is WMO (1983). Each catastrophic cyclone event reveals a spectrum of causes for major deficiencies in effective community response, some of which may not be closely related to the effectiveness of formal warning messages.

Commonly experienced response factors may be grouped into three overlapping categories:

Human (personal) factors: Age, sex, health, mobility, education and literacy, occupation, comprehension of danger, family and neighbourhood influence, cultural or religious attitudes, previous experience, poverty and economic circumstance, security of house and livestock, urban or rural residence, etc;

Hazard factors: Nature, severity and imminence of hazard(s), hazard frequency, immediate past experience of hazard including warning performance, credibility of warning service, visible evidence of threat, clarity of warnings, vulnerability of the community, etc;

Community aspects: Supporting infrastructure, availability of safe shelter and supporting welfare, extent of published evacuation planning, flood-free road access, confidence in counter-disaster officials, evidence of contingency planning, media collaboration to upgrade information, integrity of community lifeline services, level of community awareness, etc.

Figure 1 and Figure 2 illustrate the connecting links between warning content, perception, decision process, confirmation and belief that influence response and individual group action.

7.2.3 Warning Strategies in an Interdisciplinary Perspective

Many tropical cyclone specialists and forecasters have had limited opportunity to consider their particular roles of providing hazard and warning information in the perspective of a comprehensive sequential cycle of disaster management functions. The same comment applies to most personnel closely involved in natural hazard and disaster reduction functions.

Decision Processes in Response to Warning   Authentic Warning of Impending Danger   Information Are risks serious if no protective action is taken? No No action, no conflict Maybe or yes Information Are tisks serious even if action is taken? No Action, no conflict Maybe or yes Information Is there better hope of means of escape? No Defensive avoidance Maybe or yes   Is there time to do this? No Hypervigilance Panic possible   Maybe or yes Vigilance and effective coping Figure 2: The decision process in response to warning (adapted from Janis and Mann, 1977).

One estimate of the prime functions and supporting organisational, scientific, technological, educational and other supervisory interests involved in varied aspects of hazard mitigation are provided in Figs. 3 and 4. Most disaster managers consider the warning function to be a limited, though highly important part, of non-structural preparedness measures that often must proceed in relation to hazards for which little or no warning is feasible. In this respect, the availability of warnings for tropical cyclones may be considered a special bonus input to the comprehensive function of preparedness.

In respect of warning strategies the following quote indicates the varying perceptions, and thus criticisms, with which specialists may view the effectiveness of tropical cyclone warning systems:

"The perspective from which the basic organisational effectiveness of a TC warning service is examined will depend very much upon the focus of interest of the reviewer or his organisation place in the chain of events in the warning -origination - delivery - utilisation - response process. The meteorologist is anxious to see that his geophysical information, obtained by huge investment in science and technology, is usefully deployed. The social scientist will study the behavioural response of communities and individuals to a variety of warning stimuli in varied social, geographic and cultural circumstances. A systems analyst may wish to test organisation theories of human interaction in the crisis situation which the landfall of a cyclone presents, while a disaster specialist may compare all aspects of the total warning-response system in the context of other natural hazard occurrences. A politician may take advantage of perceived deficiencies in the system to plead for additional resources for his electorate, and perhaps a government economist may be anxious to compare the cost-effectiveness of various inputs into a warning system with subsequent outputs to rationalise competing demands on his budget. These and many other inter-disciplinary interests are recognised as contributing to the totality of an assessment of the usefulness of a tropical cyclone warning system." (WMO, 1990).

Among the most compelling factors which influence response to cyclone warnings are the degree of sustained community awareness of the great dangers of cyclone hazards, the perception of the credibility of the warning authority, and degree of confidence in the capacity of community officials to martial resources to implement preparedness measures. Thus an aim of warning strategies must be to take into account the roles played by the great range of interdisciplinary interests that jointly foster human response to cyclone warning and mitigation measures.

Figure 3: Disaster management cycle (Fred Cole, personal communication).

Figure 4: The disaster universe (Fred Cole, personal communication).

Contents Chapter 7.3