Impact-Based Forecasting: Moving from what weather will be to what it will do for more effective disaster risk management

What is impact-based forecasting?

In the context of weather forecasting, Impact-based forecasting (IbF) reflects a shift from describing and communicating what the hazard will be to what the hazard might do. This involves integrating data about potential hazards with information about the exposure of populations, assets, and infrastructure, and their vulnerability to hazardous events.

The World Meteorological Organisation (WMO) and the Red Cross Red Crescent Society have led the development of guidelines (most recently Red Cross Climate Centre, 2020; WMO, 2021) for implementing IbF across a range of levels and applications, such as for specific sectors, users, or areas, reflecting the different types, purposes, and uses of IbF for different stakeholders.

Gaining user insights into the research-to-operational elements of IbF

There is a huge range of methods and approaches to IbF being developed and tested by a number of groups across research, policy, and practice, enabling cooperation and collaboration across multiple fields, sectors, and disciplines. With so many key stakeholders involved, there are different perceptions and expectations of what the value and purpose of IbF is.

The Science for Humanitarian Emergencies and Resilience programme has been exploring IbF in various interdisciplinary research projects (particularly FATHUM, ForPAc and LANDSLIP projects), and through its Impact and Integration initiative has conducted a focused piece of research to answer two key questions:

• Is there a shared understanding of what IbF is across individuals involved in its development?
• Is there a shared perception of the challenges, barriers and opportunities associated with implementing IbF operationally?

The findings of the research, discussed below and available in full here, are intended to bring together insights from different IbF stakeholders engaged in developing and using impact-based forecasts for decision-making. The aim is to identify the challenges and opportunities for applying IbF research to operational practice.

What does IbF mean for disaster risk management?

IbF enables more effective and efficient disaster risk management by providing stakeholders with actionable information about where and when a hazard is likely to happen, how severe it is likely to be, and what impacts it is likely to have. Disaster risk managers and decision-makers in the public and humanitarian sectors can then make informed decisions about what resources are needed, at what scales, and in what location, enabling early and anticipatory response instead of responding once a disaster has occurred. This mitigates the impacts of a given hazard event on communities, shields against the cumulative erosion of resilience of households, infrastructure, and livelihood sectors to subsequent hazard events, and thereby protects development gains.

Additionally, it supports the cost-effectiveness of disaster risk management, which is of particular importance in contexts of high pressure on scarce resources. For example, having the lead time available to pre-position goods using road transport is cheaper than emergency last-minute transport by air. Efficiency is also supported by having time to update and refresh standard operating procedures and early action protocols, ensuring that staff are familiar with these protocols and resources can be deployed appropriately.

IbF also enables disaster risk managers to plan for responses that are inclusive of vulnerable and marginalised groups. People affected by social and economic injustice which increase their vulnerability to disasters are often overlooked in emergency response, as disaster risk managers do not have the time to understand specific needs, let alone incorporate these into evacuations, distributions, or temporary shelter arrangements. With data about where impacts will be felt, what these impacts will be, and who will experience them, disaster risk managers can ensure that different needs are considered and accommodated for in the response. For example, if there are informal settlements located in an area, this may have implications for how many affected people will have identity documentation, which is often needed to access aid, flagging a need to develop an alternative registration and distribution process.

What is needed for IbF?

For IbF to be effective, it needs two key things: data and collaboration. In terms of data, IbF represents a major shift in forecasting and requires significant data inputs in relation to hazard, exposure, and vulnerability. Hazard data will include a combination of monitoring and historical observations about indicators such as rainfall, vegetation cover, soil moisture, and historical impacts; exposure data will include maps of the locations of households, infrastructure, and livelihood sectors.

Vulnerability data may include poverty and literacy levels, population density, disposable household income, and market access, as well as social indicators about health, nutrition, gender and social inclusion. This data is particularly complex for a number of reasons: firstly, it is highly dynamic, and changes over time as well as being highly influenced by changes to the context such as land use planning and development, or recently Covid-19. Secondly, this data is hard to capture in ways that are comprehensive, consistent, and manageable to keep up-to-date – different types of vulnerability data may also be collected and held by different actors, and can be difficult to share or synthesise. Finally, vulnerability data can be difficult to quantify, and a reliance on quantitative data risks excluding people and vulnerabilities which are less visible or measurable.

In terms of collaboration, IbF involves the experience and expertise of a range of stakeholders working at different levels, including hydrometeorological agencies and non-governmental organisations involved in coordinating and delivering disaster risk management. Collaboration brings together the different types of skills, knowledge, and material resources needed in order to collect, analyse, and manage the required data, develop and interpret relevant forecast information, and link these forecasts to effective early actions.

What roles can disaster risk managers play?

Disaster risk managers have key roles to play in developing and delivering IbF. Their knowledge of the risk facing communities, and the varying vulnerabilities that affect risk thresholds and needs, are key to determining what information IbF needs to provide (as well as when and how to provide it). This also relates to providing exposure and vulnerability data in order to produce the forecasts, and ensuring that communities at risk of disaster are included and represented in the process.

For IbF to be effective, disaster risk managers need to be involved as active participants, moving away from simply receiving information that does not sufficiently support decision-making and action. Working together with other key stakeholders to meaningfully forecast likely impact is a complex and challenging process, requiring time, funding, and coordination support. But is has significant potential benefits for effective early action which can mitigate the impacts of disasters on communities.