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Disaster Prevention and Mitigation

Examples of Weather Warnings

The hazard-disaster relationship

No country can be considered immune from natural hazards which, by definition, cannot be avoided. But most natural disasters can be mitigated and the adverse effects of many, significantly reduced. Hazards can become disasters only when people, their villages, towns and activities are located in the area affected by the hazard. The link from hazards to disaster is vulnerability and whereas nothing can be done to prevent the occurrence of a hazard, the vulnerability of an area can be expertly assessed and prescriptive action taken to decrease the risk of loss when extreme weather events occur.

The PWS Programme approach to disaster reduction

The purpose of the WMO PWS Programme is to assist Members to provide reliable and effective weather and related services for the benefit of the public. NMHSs generally provide a variety of routine forecasts and information to enhance the social and economic well-being of nations but these vary from country to country, depending on national practices. However, a core goal common to all NMHSs, centres on ensuring the safety of life and property, which is one of the primary responsibilities of a government.

Planning for disaster reduction

Each WMO Member is aware of the need for, and should have, a complete action plan for natural disaster reduction, which involves the four phases prevention, preparedness, response and recovery. The prevention phase involves long-term activities to identify the vulnerability of an area prior to impact, and is aimed at reducing the occurrence and/or the effects of a disaster. The preparedness phase also involves long-term activities to increase the effectiveness of emergency response during a disaster. It is a strategy for real-time co-ordination and response to a disaster situation and includes citizen education and awareness, ensuring the availability of critical warning information, hazard awareness drills and exercises, identification of effective dissemination systems and backup plans in case of failure of some aspect of the plan. The NMHS is a major provider of data to experts in prevention planning and plays a major role in the preparedness phase.

Factors contributing to ineffective warnings

It must be acknowledged however, that even with an excellent strategy in place, plans can go awry for many reasons resulting sometimes in confusion at the approach of a known hazard and during the disastrous event. In fact, this confusion at a critical time can even contribute to the exacerbation of the disaster. To be successful, a warning strategy should strive to ensure that everyone at risk receives the warning, understands the information presented, believes the information, personalises the risk, makes correct decisions and responds in a timely manner. Assessments in the aftermath of meteorological and hydrological disasters point to the following reasons for the ineffectiveness of some warnings:


  • Forecast inaccuracy - miscalculating onset time, intensity or effects of the hazard;
  • The NMHS is not the ''sole authority'' for preparing and issuing warnings;
  • Inadequate, ineffective or failed communication and/or dissemination systems;
  • The availability of unofficial and sometimes contradictory information on the Internet and international television broadcasts that could lead to public confusion;
  • The low credibility of the NMHS, based on public perceptions of NMHS capability;
  • Lack of timeliness of warnings and unavailability/inadequacy of updates;
  • Ineffective, haphazard and ad hoc co-ordination with local and national disaster managers and other decision makers, even the media, mainly radio and television;
  • Public response - people make their own assessments based on things such as previous experience and security of property, and may decide to take risks;
  • The warning itself - vague, equivocal, ambiguous or not easy to understand language;
  • insufficient advice on what to expect and actions to take;

The above list could be expanded to include NMHS staffing inadequacy, not enough real time field data to adjust/update warnings to include specific areas, or even an inadequate disaster reduction plan.




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