|Volume 59(1) January 2010
Public weather services for disaster risk reduction
National Meteorological and Hydrological Services (NMHSs) all over the world have an essential role to play in bringing about disaster reduction through delivery of quality public weather services, including the provision of weather forecasts, early warnings on hazardous weather, outreach activities to enhance public awareness of weather hazards, interpretation and use of the weather information, as well as collaboration with disaster relief organizations to minimize loss of life and property. Although the damage statistics due to natural disasters are still on the rise globally, in some places, the damaging effects of weather-related hazards have gradually become more or less harnessed over the years. In Hong Kong, for example, over the past five decades, the number of casualties caused by tropical cyclones has declined (Figure 1).
As WMO celebrates its sixtieth anniversary, it is important to trace the development of public weather services in relation to disaster preparedness and mitigation and to point to what NMHSs can do in future. Effective disaster reduction may be attributed to strengthened infrastructures against the elements and continual advances in weather monitoring and prediction, as well as the readiness of the public to respond as a whole to weather warnings.
Early warning systems – science or service first?
Weather warnings a century ago were rudimentary at best. Imagine the time before the age of meteorological satellites, or even before the telegraph became a common feature onboard ships — some weather services were already operating, or committed to operate, typhoon warnings. These weather services had to be content with the scarce or inadequate information and observations they had when deciding on issuing weather warnings.
Over the past 60 years as population has grown with increasing urbanization and economic activities have expanded with increasing diversity, society has had a greater demand for weather warning services to protect life and property against weather hazards. Partly in response to this demand and partly due to the advances in monitoring and prediction capabilities, early warning systems have developed and grown over the years in variety, covering such hazards as tropical cyclones, high winds, heavy rain, snow, thunderstorms, extreme temperatures, droughts and reduced visibility.
Despite the advances, limitations in weather forecasting remain to this day. A case in point is the warning of heavy rain, where accurate prediction of rainfall for the next few hours remains very difficult if not impossible. Nonetheless, many NMHSs are issuing, or committed to issue, warnings of rainstorms.
Warning systems have grown in complexity, with warnings often graded in levels, each triggering different response actions by the public. The time scale of warnings has also evolved from days to hours to minutes, in accordance with synoptic-scale, down to meso-scale or even to local-scale phenomena (such as tornadoes).
Overall, these warnings have been effective in disaster prevention and reduction. However, it is apparent that NMHSs often have to, or are under pressure to, provide services even before the relevant science is established or the technology is available.
Time and space
Timely delivery of warnings to the public is an essential element of effective warning systems. Back in the 1950s, radio and visual signal stations were often used to communicate weather warnings to the public. With the advent of television in the 1960s, radio and television have become the preferred channels for obtaining warning information. One limitation of radio and television is that the airtime is normally short, making it necessary to disseminate simple and direct warning messages that carry advice on protective measures to take. However, even today, radio and television remain a convenient source of warning for the public and an indispensable dissemination channel for the underprivileged such as the elderly and the poor.
To fully utilize these means of communication, NMHSs work closely with the media to ensure that warning information is quickly and accurately disseminated through regular broadcasts. Nowadays, NMHS personnel often appear on television and radio to provide expert briefings on impending and potentially hazardous weather events. In the meantime, automatic weather answering machines have also become more popular, allowing the public to access the latest information on the phone. These various means are very effective in rousing public attention and in disaster preparedness and prevention.
The advent of personal computers in the 1980s and that of the Internet in the 1990s offered unprecedented opportunities for fast delivery of voluminous information, enhancing the effectiveness of early warning systems. They have enabled people to access weather information in both audio and pictorial form with easy-to-understand and highly interactive graphics. Many NMHSs now operate Websites for fast and almost immediate promulgation of weather forecasts and warnings. Millions of Internet users can now learn of the latest status of warnings in a matter of minutes. For example, the number of visitors to the Hong Kong Observatory Website has steadily increased over the past decade, while the number of dial-in callers to an automated recording system has remained steady (Figure 2).
In addition to a “pull”, the Internet also allows an information “push” to the user. It also makes individual alerting and customization possible. A case in point is the provision of lightning location information on the Hong Kong Observatory Website. Here, a user may pick a location of interest and choose up to three alert range circles for receiving distinct audio and/or visual alarms when lightning occurs within a particular alert range (Figure 3). Coupled with geographic information, user-specific alerts thus provide fast and very relevant information, which is conducive to prompt and effective response actions.
The Internet thus enables the provision of a variety of weather information and data to individual users. This is especially helpful for sophisticated users who are well versed with computers and have a good understanding of the weather and of how the information can be used in risk evaluation and in decision-making. A recent development arises from the increasing popularity of Wi-Fi in city areas, which makes it possible for people using a portable device to receive automatically the latest site-specific information, for example temperature and weather from the closest weather station (Figure 4).
Mobile technology, especially in the past decade, has proven to be a very effective means for timely delivery of weather warnings and information to people on the move. Such devices are particularly suited for warning of rapidly developing hazards such as thunderstorms and flash floods. Short message service (SMS) can be pushed to users anytime anywhere to prompt them to take appropriate precautions. The high rate of use of mobile phones in some places, such as south China, has made it possible for the weather service to issue localized warnings to users geographically located within a particular telecommunications cell. This way, mobile phones become a valuable tool for fast and effective warning delivery.
Caring for the young and old
In the past few decades, NMHSs have come to realize that in order for warning systems to be effective, it is not sufficient to just sharpen forecasting skills and enhance technical capabilities. They must also work with people and stakeholders to raise their awareness of weather hazards, and to ensure their understanding of the meaning of warnings and the appropriate response actions to take. Thus, NMHSs find themselves investing an increasing amount of time and resources in reaching out to the public. These activities take the form of public talks and lectures, exhibition and campaigns, publications of pamphlets and publicity videos, writing articles for the print media, and organizing open days, school talks and joint events with non-governmental organizations.
In delivering their warning services, NMHSs must take account of the underprivileged, including the elderly and the young. For instance, warnings on extreme temperatures, namely very hot and cold weather, have been set up by an increasing number of NMHSs in recent years. These warnings cater to the sick and elderly who are particularly vulnerable to extreme weather, sometimes necessitating the activation of social welfare personnel and opening of shelters by municipal authorities.
Weather education is especially effective for the young. Places in Europe, North America and Asia have started establishing networks of so-called community weather stations, most commonly in schools. Relatively inexpensive and easily connected to the Internet, information from these stations greatly facilitates young people’s appreciation of the weather and their awareness of climate and climate change (Figure 5).
As young people are attracted to electronic media, NMHSs can exploit popular utility Websites to their advantage. A weather programme or a weather briefing on such Websites as YouTube finds audience among young people (Figure 6). NMHSs can take advantage of the same channel to promote science education by carrying clear and succinct expositions on such subjects as severe weather phenomena and climate change.
Role in emergency response system
In the past few decades, NMHSs have learned, often through bitter experience, that despite good forecasts and warnings, great damage and heavy losses could still be inflicted on the community if the emergency response system failed to function properly. Thus over the years, NMHSs, as the triggering agencies in emergency response, often have taken on a major or leading role in the development of contingency planning for natural disaster reduction.
NMHSs provide data in the planning stage, participate in exercises and drills in preparation stage, interact actively with stakeholders during the execution stage and improve upon relevant procedures in the review stage. Close cooperation between the NMHSs and security, civil defence, emergency relief, search and rescue agencies is essential in these endeavours.
Users of weather services often comprise a wide spectrum of people and sectors. It is thus important that regular communication is established with various weather-sensitive sectors, including education, transport, logistics, engineering and tourism. Liaison groups established by NMHSs with the aviation and marine communities have become increasingly common.
One form of liaison with the public sector involves the establishment of voluntary groups. With proper training, volunteers can advise on proposed new services by the NMHSs, provide guided tours, create simple instructions on weather observation and educate on weather phenomena.
Public opinion surveys are effective and indispensable tools whereby NMHSs can gauge their own performance in the mind of the public and identify improvement areas especially in severe weather warnings. This way, NMHSs are able to better understand public needs and adjust their services appropriately to make them more relevant to users.
In the dialogue with the public, NMHSs can also share with users the limitations of weather forecasting in order to manage user expectations. This helps build and maintain a trusting relationship with the public and contributes to the overall effectiveness of their service.
WMO has played an important role in the development of public weather service for mitigating the effects of weather hazards. Under its framework, weather observations are regularly exchanged among NMHSs, and model prognoses from advance numerical weather prediction (NWP) centres, which form the backbone of public weather services, are freely available to NMHSs. WMO has promoted capacity building to help Members strengthen their public weather services for disaster reduction through sharing of best practices, publication of guidelines, expert missions, transfer of knowledge and technology, and organization of workshops, seminars and projects.
As least developed countries generally lack the necessary computing facilities for processing NWP output, they have been unable to make use of the NWP guidance in their operational forecast. Hence, WMO has taken effort to enable such Members to benefit from the advances in NWP. A case in point is the pilot project on the city-specific forecast in the Regional Association II, which comprises Asia. In this project, NWP centres in the region generate city-specific forecasts of surface parameters and make them available to participating Members through the Internet on a daily basis. Such processed forecast information is particularly useful to least developed countries as they can be readily applied to their forecast operations. Another example involves the conduct of a forecast demonstration project in Africa (Regional Association I) recently, whereby participating Members were able to acquire experience and knowledge in nowcasting, resulting in improved services.
Weather warnings and information are becoming increasingly indispensable for the global community and mobile public. They allow travellers to better plan their trips and protect themselves against weather hazards Official warnings and information on tropical cyclones over the world are now accessible in one single Website — the Severe Weather Information Centre (SWIC) Webpage, which is operated by the Hong Kong Observatory on behalf of WMO (http://severe.worldweather.wmo.int). Apart from tropical cyclones, the Website also covers other severe weather types such as heavy rain/snow and thunderstorms. A trial is in progress on the SWIC platform to allow a registered individual to be alerted whenever severe warning warnings are issued by a participating official weather service for its country/region.
Building a stronger future
The development of public weather services has played an important role in the mitigation of natural disasters over the past 60 years and will continue to be so in the years to come. Oftentimes, NMHSs have to face a demand for service even before the relevant science and technology are established. The needs of society help drive the development of public weather service, with the support of advances in science and technology. This is especially true as society grows and becomes more sophisticated.
NMHSs, however, should not lose sight of the need to serve the underprivileged, including the elderly and the poor. It is the same for the issue of climate change, where the underprivileged is most affected. Public engagement is thus indispensable on the part of NMHSs. They should assist least developed countries to the extent possible so that they can benefit from advances in science and technology, whose adoption is vital for the provision of quality weather service for strengthening resilience against hazardous weather.
With climate change, it is likely that extreme weather events, such as heavy rain, severe droughts and extremely hot weather with greater intensity, will affect more people in the future. This trend poses a challenge for the skilful forecast of extreme weather events and for more comprehensive warning and emergency response systems to mitigate the damaging effects of extreme weather events. On the very short-range front, improvement in nowcasting skills and application of communication technology will result in more effective warnings with longer lead time for fast-developing severe events such as thunderstorms and gust fronts.
Public education will be essential in reminding people to beware of weather hazards, to understand the weather warnings and to take responsive actions in a timely manner. Indeed, public weather services will continue to play the very important role of protecting life and property and mitigating the effects of natural disasters.