Dr. Hwirin Kim, chief, Hydrological and Water Resources Services Division, and Petra Mutic, Flash Flood Guidance System project manager, at the World Meteorological Organization provide insight into how to build and improve flash flood resilience globally.
What is the FFGS and how does it work?
The Flash Flood Guidance System (FFGS) is a forecaster’s tool designed to provide hydrologists and meteorologists with readily and accessible observed and forecast data, and other information to produce timely and accurate flash flood warnings.
Flash floods are among the world’s deadliest natural hazards. They cause more than 5,000 deaths annually and have severe social, economic and environmental impacts.
The FFGS is implemented on regional and country scales and uses flash flood guidance as the basis for trained forecasters at national meteorological and hydrologic services (NMHSs) to use operationally to develop flash flood warnings. Important technical elements are the development and use of a bias-corrected satellite and radar precipitation estimates, the configuration and implementation of mesoscale weather prediction models for high resolution surface precipitation fields, and the use of physically based hydrologic modeling to determine flash flood guidance, flash flood threats and risks for basins. In addition to research and technical development and implementation of systems, the project includes extensive technical training programs on flash flood prediction for country hydrological meteorological service personnel, as well as disaster managers.
Today, FFGS is providing the information for flash flood warnings in 67 countries to some three billion people – 40% of the world’s population – as a result of 13 regional and two national FFGS projects. Since the implementation of FFGS, most of the countries using it have had access for the first time to products that enable them to issue flash flood warnings and provide response-agencies with the ability to mobilize rapidly.
What are some of the recent key FFGS achievements?
Latest achievements include the development of the FFGS centralized online training platform, a one-stop-shop for trainers and trainees to access free distance learning resources, including hands-on material, case studies and videos, to ensure that no one is left behind.
A training simulator interactive application is now being used to train operational forecasters in the effective use of necessary data and products to improve flash flood forecasting skills and actionable communication with the users of flash flood warnings. The simulator has been adopted for different FFGS regions and it utilizes real world scenarios in which a flash flood may or may not occur. This requires the user to make an assessment based on the knowledge they have available and assess their skill and understanding of the unique characteristics of flash floods.
Also, we are very pleased to share that the Turkish State Meteorological Service (TSMS), which acts as the Regional Centre for Southeast Europe FFGS (SEEFFGS), developed the app, which generates the alerts once the SEEFFGS indicates a possible flash flood threat or risks. The app supports the daily operational work of the forecasters and assists them to produce timely and accurate flash flood warnings. The app provides detailed information about the possibility of flash flood occurrence, its location (county and sub-basin), sufficient lead-time to issue flash flood alerts and warnings, and other important information such as intensity of forecast precipitation and state of soil moisture. The powerful heads-up notification app is greatly appreciated by the SEE countries and other regions have expressed interest in using it.
How is the FFGS especially beneficial for developing countries?
Recognizing a lack of capacity at NMHSs, especially in developing countries, and an expressed need for flash flood warnings worldwide, WMO, the US Agency for International Development (USAID), NOAA and the Hydrologic Research Center (HRC) in 2009 started a cooperative initiative to implement FFGS throughout the world. FFGS is providing these countries with the information, technology, training, capacity building, protocols and procedures to ensure the population at risk receives flash flood early warnings and can act on them.
Education and training lie at the heart of development efforts; without human resources development, most development interventions would be ineffective. FFGS activities in this area aim to help participants to increase their knowledge, skills and understanding and to develop the capabilities and competencies needed to issue timely, accurate and actionable flash flood warning. Training is not limited to NMHS staff, but also include specialized agencies that have defined responsibilities and public duties related to flash floods.
After the implementation of the FFGS, more than 40 countries for the first time had developed the capacity to issue flash flood warnings and started doing flash flood verification studies which help them to understand the uncertainties and limitations of FFGS, forecasts and warnings and the ways in which they can be improved. Countries also strengthened collaborations between NMHSs and national disaster management offices (NDMOs) and initiated first of kind flash flood public awareness initiatives.
How do flash flooding warning systems vary from the most developed to developing countries?
Each country will have its own unique requirements and operating conditions, and no single system will work for everyone. But all effective systems share certain common features. Development and sustainability of the early warning system requires political commitment and dedicated investments. Also, a flash flood early warning system (EWS) does not have to stand alone but can be a system within a multi-hazard early warning system (MHEWS).
Comparing to a developing country, the first world countries have dense hydrometeorological observing networks, good radar coverage, access to the newest satellite algorithms, super computers, high resolution computer models of atmospheric processes and distributed hydrologic models, 24/7 forecasting systems that are able to adopt to the constantly changing information technology, well-understood protocols for issuing warnings and communication systems to ensure that EWS are effectively implemented.
It is important to say that flash flood events could still be missed by even these most sophisticated warning systems due to science’s inability to always pinpoint the exact location and timing of small-scale heavy rain.
Proper investment in the development of a “Concept of Operations” is one of the most effective strategies for a flash flood EWS. Building partnerships, targeting communications and training, and creating local ownership are just some of the strategies that promote successful flash flood EWS.
Does more need to be done to assist developing countries with flash flooding awareness?
Flash flood public awareness should be ongoing in every country, not just developing nations. Successful response to flash flood warnings is most likely to occur when the people receiving the warning messages have been educated about the characteristics of the flash floods and are familiar with the extent of possible damage that could result. To ensure that the population has sufficient knowledge to understand the flash flood risk, public education campaigns should be conducted by NMHSs and/or relative agencies on regular and as-needs basis. Public awareness initiatives are generally more effective when they are carried out by an NMHS in partnership with emergency and management agencies.
It is no longer enough to provide a good forecast, people are now demanding information about what to do to ensure their safety and protect their property. There is still a gap in many countries between forecasts and warnings and understanding their potential impacts, both by the emergency management agencies and by the population at large. It is becoming urgent for developing countries to make the transition from focusing only on the accuracy of hazard-based forecasting to also outlining the potential impacts of a forecast – an evolution from “what weather will be” to “what weather will do”.
What does the future hold for FFGS?
Scientists expect the frequency and severity of flash floods to increase due primarily to climate change, population growth and land-use changes. The world’s urban population is expected to increase from 55% in 2018 (some 4.2 billion people) to 68% by 2050. Continuous urbanization increases the size and frequency of flash floods and may expose communities to increasing flood hazards. Special FFGS modules and components are available to assess landslide threats, flash flood events in urban areas and riverine routing.
Development and implementation of the sustainable and adjustable FFGS is, therefore, more crucial than ever to protect communities, safeguard economies and save countless lives. Together, FFGS partners, participating countries and regions will continue to mitigate the impacts of flash floods by enhancing early warning capabilities.
What are some of the key challenges still present in predicting flash flooding?
There are challenges still present in flash flood prediction and to establish a fully functional end-to-end forecasting system. In a case of rapid-onset events like flash floods, time is the most critical factor. To provide effective warnings, the forecasts should be made with adequate lead-time. It may never be possible to prevent flash flooding and producing flash flood forecasts for any particular location is likely to remain challenging beyond a few hours in advance – there will always be limits to the predictability of precipitation, such as uncertainty. But our capacity to predict extreme weather is constantly improving. The recent nowcasting models and ensemble forecasting have resulted in significant advances in forecasting rainfall.
The development of methodologies capable of incorporating forecast uncertainty into the decision-making process is, however, one of the major challenges in flash flood forecasting and warning.
There are also concerns related to the great variety of data formats, the availability of public versus private data, the reliability of data delivery to the system, the asynchronous arrival of data and a mix of space–time data resolutions. The 2021 Extraordinary World Meteorological Congress approved the WMO Unified Data Policy. The data policy update will help the WMO community strengthen and better sustain monitoring and prediction of all Earth-system components, with massive socioeconomic benefits as a result. It will lead to additional exchange of all types of environmental data, which in turn will enable all WMO members to deliver better, more accurate and timely weather- and climate-related services to their constituencies.
An accurate and timely warning does not guarantee safety of life and property. Even the best forecast, issued on time, will have little impact if did not generate desired response from those at risk. This can be overcome by evolving toward impact-based forecast and warning services which requires close collaboration between NMHSs, NDMA, other stakeholders and public. The improvement of knowledge and public awareness of flash floods is therefore another challenging but very important part of an effective forecasting system.
How can the information chains be improved to ensure citizens receive warnings in time?
Close coordination must occur between all sectors and between national and local governments for the system to function properly, with clear lines of roles and responsibilities to avoid confusion and chaos during disasters. An important part of the process are the systems enabling user feedback to periodically improve and address the needs of decision makers.
Because flash flood hazards do not recognize national boundaries, transboundary/regional programs and cooperation are essential to reduce the loss of lives and damage. The development and implementation of systems to provide early warnings for flash floods requires data and information sharing in real time, and coordination among the government agencies at all levels. It is of primary importance that early warning systems are truly end-to-end in nature. Each component in this process is critical to reduce the impacts of hydrometeorological extremes and provide essential lead times to aid decisions. The failure of one component will lead to the failure of the entire system to save lives and livelihoods.
Ongoing advancements in communication, media and mobile technology and its widespread availability will potentially simplify the dissemination of flash flood warnings to the public.
In order to disseminate the alerts to as many people as possible in a timely manner, NMHSs need to be able to send a consistent alert message through multiple communication channels such as radio, television, landline telephone connections, mobile phones, internet, fax and sirens. The Common Alerting Protocol (CAP) standard is key to supporting such standards-based, all-hazards, all-media public alerting.
Is there anything else you would like to add?
I always say this to members, partners and colleagues: There is no single perfect flood forecasting system. We must ensure ownership by all and that no country is left behind. All our efforts and actions will surely make possible to protect more and more people’s life and properties.
To find out more about how the WMO and ECMWF are bolstering their flash flood prediction services to save lives, read our flash flooding feature in the latest issue of Meteorological Technology International by clicking here.
