Impact-Based Forecasts and Warnings: Challenges and future research directions
- Sally Potter
- Jan 27
- 9 min read
Weather-related hazards can cause significant harm to people and property. To help reduce these impacts, impact-based forecasts and warnings (IBFW) are increasingly being used. This article summarises our recently published open-access article on IBFW systems (Potter et al., 2025) highlighting key challenges and areas for future work.
What are Impact-Based Forecasts and Warnings?
Traditional weather warnings are triggered by the severity of the hazard itself, such as how much rain will fall or how strong winds will be. In contrast, IBFW systems aim to communicate the potential impacts of severe weather, such as "possible flash flooding that could damage homes and block roads."
The goal is to make warnings more meaningful to the public, increasing the chances that people will take protective action. Many weather agencies around the world are now working to implement IBFW approaches. You can see more about what impact-based warnings are on my blog post here.
Why are Impact-Based Warnings important?
In March 2022, the United Nations called for everyone on Earth to be protected by early warning systems by 2027. This ambitious goal, called "Early Warnings for All," recognises that effective warnings can save lives and reduce disaster impacts.
At the same time, humanitarian organisations and emergency managers are shifting from just responding after disasters to taking early action to reduce impacts before they occur. Understanding and communicating potential impacts is key for both improved warnings and early humanitarian action.
Key challenges in developing IBFW systems
While IBFW systems show great promise, implementing them can be complex and costly. To explore these challenges, the World Meteorological Organization's World Weather Research Programme High Impact Weather project held a series of virtual workshops in late 2022, involving a team of 15 scientists from 8 countries. Over 350 experts from 52 countries participated.
We explored how to define the success measures for IBFW systems, highlighting the importance of defining clear objectives for IBFW systems. Key points are:
Success measures should align with the goals of reducing impacts and improving decision-making.
Metrics could include lives saved, property protected, and economic losses avoided.
Evaluation should consider both the warning system's performance and its societal impacts.
Challenges include attributing outcomes to specific warnings and accounting for varying levels of exposure.
Long-term tracking is needed to assess IBFW effectiveness over time.
We identified ten key themes related to IBFW challenges:
Let’s look at each of these in more detail.
Evaluation and verification of IBFW
Evaluating the effectiveness of IBFW systems is complex and crucial. We need robust methods to assess both the performance of warning systems and their societal impacts. A major challenge is the difficulty in attributing outcomes to specific warnings. It is important to collect comprehensive impact data at appropriate scales, suggesting the exploration of innovative data sources.
Our findings emphasise the necessity for long-term tracking to truly understand the value of IBFW systems over time, including estimating losses that were avoided due to warnings, and how people responded to them. This is particularly important given the changing climate and societal conditions.
Developing evaluation frameworks that can accurately measure the success of IBFW systems is a critical research priority. This includes methods for estimating avoided losses and tracking behavioural responses to warnings.
We need to research what types of warnings actually lead to better decisions and reduced impacts, and in which contexts? What aspects are most important for an effective system?
Communication and uncertainty
Our research found that communicating uncertainty is seen as a critical challenge. We identified several key issues in this area. First, there's a need to balance providing detailed uncertainty information with the risk of overwhelming users. We also noted the importance of tailoring uncertainty communication to different user groups, as their needs and understanding levels vary. We need to explore the role of intermediaries (such as media) in communicating IBFW.
It is challenging to explain the compounding uncertainties in IBFW systems, which involve both weather and impact forecasts. We need to explore how to present information about vulnerability and exposure to hazards.
More research is needed to develop effective strategies for communicating these complex uncertainties in ways that support better decision-making.
Responsibility
The issue of responsibility is complex and multifaceted. There is a need for clear delineation of roles and responsibilities among various stakeholders involved in IBFW systems. This includes meteorological services, emergency management agencies, and other partners.
Our research revealed challenges in determining who should be responsible for different aspects of IBFW, such as impact modelling, vulnerability assessments, and warning dissemination. These responsibilities often vary between countries and regions.
It is important to collaborate and grow partnerships in developing effective IBFW systems. However, we also recognised that such collaborations can raise questions about data sharing, liability, and decision-making authority.
Our findings suggest that further research is needed to explore optimal governance structures for IBFW systems, particularly in multi-hazard contexts where multiple agencies may be involved.
Scale and resolution of IBFW
The appropriate scale for IBFW can vary significantly depending on the hazard type and local context. For instance, flash floods may require highly localised warnings, while heat waves might be addressed at a broader scale.
Our research highlighted the tension between providing detailed, location-specific information and ensuring warnings are manageable and actionable. We found that increasing resolution doesn't always lead to better outcomes if it overwhelms users or introduces excessive uncertainty.
It’s important to align IBFW scales with available impact data and decision-making processes. This alignment can be challenging, especially when dealing with multiple hazards or cross-border events.
Our findings suggest a need for further research on optimal scales for different IBFW applications, considering both scientific capabilities and user needs.
Interoperability
We identified a growing need for IBFW systems to work seamlessly across different platforms, agencies, and even countries. This is particularly important for hazards that cross jurisdictional boundaries or require coordinated responses from multiple organisations.
Achieving interoperability often requires standardisation of data formats, communication protocols, and warning levels. However, it is a challenge to balance standardisation with the need for locally tailored approaches.
Interoperability extends beyond technical systems to include shared understanding of terminology, risk thresholds, and decision-making processes among different stakeholders.
Our research indicates that improving interoperability could enhance the efficiency and effectiveness of IBFW systems, particularly in multi-hazard scenarios. However, we also recognised that implementing truly interoperable systems often requires significant investment and coordination.
Input variables
There is a need for a wide range of input data to create meaningful IBFW, including not just weather forecasts, but also information on exposure (where people and assets are located), vulnerability (how susceptible they are to damage), and past impacts. However, obtaining and integrating these diverse data sources can be challenging.
Our findings suggest that the quality and resolution of input data significantly affect the accuracy of impact predictions. While high-resolution data can improve forecasts, it also increases computational demands and may introduce additional uncertainties.
Dynamic input variables that can capture rapidly changing conditions, such as population movements or short-term changes in vulnerability, could become increasingly important. However, there are difficulties in obtaining and incorporating such real-time data, and we recommend cost-benefit studies on whether dynamic exposure and vulnerability data significantly enhances the effectiveness of the warnings.
Our research indicates that selecting appropriate input variables often requires balancing scientific accuracy with operational feasibility and user needs. We found that this balance can vary depending on the specific hazard, location, and intended use of the IBFW system.
Tailored warnings
There is a growing need to customise IBFW for different user groups, as their vulnerabilities, exposure, needs, and capacities can vary significantly. This tailoring could involve adjusting the trigger thresholds, content, format, or delivery method of warnings.
While personalised warnings may be more effective, they also require more resources to develop and maintain. It is challenging to balance the benefits of tailoring with the costs and complexity involved.
Effective tailoring often requires in-depth understanding of different user groups, which can be difficult to obtain and keep up to date. This is particularly challenging in diverse or rapidly changing communities. Additionally, there could be the perception of inconsistencies when neighbours get different tailored warnings, which requires further research.
Tailoring warnings could potentially improve their effectiveness, but more evidence is needed to quantify these benefits and determine the most efficient approaches to customisation. How much tailoring is feasible and worthwhile?
Knowledge translation
There is a significant gap about how knowledge can be successfully conveyed through the warning value chain. Our findings suggest that bridges need to be constructed across disciplines, and there needs to be improved communication and collaboration between researchers and practitioners, institutions, and across boundaries.
One challenge is connecting the impacts and risks of coming events with actions that people can take in warning messages. This is particularly challenging in multi-hazard situations.
Effective knowledge translation often requires developing practical tools, guidelines, platforms, and training materials that make information accessible, and enables the sharing of experiences, including between countries. However, we noted that creating these resources requires additional effort and expertise.
Cost and feasibility
Implementing IBFW systems often requires significant investment in data, modelling capabilities, and staff training. Our findings suggest that these costs can be a major barrier, especially for organisations with limited resources.
The feasibility of IBFW systems varies depending on local contexts, including available data, technical capabilities, and institutional arrangements. What works in one setting may not be directly transferable to another.
There's often a trade-off between the sophistication of IBFW systems and their operational feasibility. We found that while more complex systems might provide more detailed information, they can also be more challenging and costly to maintain.
There is a need for cost-benefit analyses to help organisations determine the appropriate level of investment in IBFW systems. However, we also noted the challenges in quantifying the benefits of improved warnings.
Multi-hazard complexity
Many scenarios involve multiple, interacting hazards, which can be difficult to capture in IBFW systems. These complex scenarios often lead to cascading or compounding impacts that are challenging to forecast and communicate.
Developing IBFW for multi-hazard situations requires integration of diverse data sources and models, which can be technically challenging and resource intensive. There is a need for improved methods to combine information from different hazard types and impact models.
Our research indicates that communicating multi-hazard risks effectively is particularly difficult, as it involves explaining complex interactions and uncertainties to diverse audiences. We need innovative approaches to present this information in clear, actionable ways.
Multi-hazard IBFW systems often require collaboration across different agencies and disciplines, which can raise governance and coordination challenges. Our findings suggest that addressing these institutional barriers is crucial for effective multi-hazard warnings.
More research is needed on how to effectively warn for multiple, interacting hazards. This includes both simultaneous hazards (like wind and heavy rain during a storm) and cascading hazards (where one event triggers others, like rain and landslides).
Conclusion
Impact-based forecasts and warnings have great potential to help save lives and reduce disaster impacts. However, significant challenges remain in developing and implementing these systems effectively. By addressing the research priorities outlined here and described further in our new journal article, we can build a stronger foundation for IBFW approaches. This work is especially urgent as climate change is expected to increase the frequency and severity of many weather-related hazards.
Ultimately, the goal is to provide more meaningful, actionable warnings to help communities prepare for and respond prior to dangerous weather events. While much work remains, IBFW systems represent an important step toward building a safer, more resilient world.
I would like to acknowledge our workshop participants, and my wonderful team of international researchers:
Thomas Kox, Brian Mills, Andrea Taylor, Joanne Robbins, Carolina Cerrudo, Faye Wyatt, Sara Harrison, Brian Golding, Will Lang, Adam Harris, Rainer Kaltenberger, Stefan Kienberger, Harold Brooks, and Andrew Tupper.
Additional resources:
This article summarises the following open-access publication:
Potter, S., Kox, T., Mills, B., Taylor, A., Robbins, J., Cerrudo, C., Wyatt, F., Harrison, S., Golding, B., Lang, W., Harris, A.J.L., Kaltenberger, R., Kienberger, S., Brooks, H., Tupper, A. (2025). Research gaps and challenges for impact-based forecasts and warnings: Results of international workshops for High Impact Weather in 2022. International Journal of Disaster Risk Reduction, 105234, ISSN 2212-4209, https://doi.org/10.1016/j.ijdrr.2025.105234
Full references are listed in there; however, several key articles that relate to this post are:
Golding, B. (2022). Towards the “Perfect” Weather Warning: Bridging Disciplinary Gaps through Partnership and Communication, Springer International Publishing, 10.1007/978-3-030-98989-7
Potter, S., S. Harrison, & P. Kreft (2021). The benefits and challenges of implementing impact-based severe weather warning systems: perspectives of weather, flood, and emergency management personnel, Weather, Climate, and Society 13 (2). 303–314, https://doi.org/10.1175/WCAS-D-20-0110.1.
Harrison, S.E., S.H. Potter, R. Prasanna, E.E.H. Doyle, & D.M. Johnston (2022). Sharing is caring’: a socio-technical analysis of the sharing and governing of hydrometeorological hazard, impact, vulnerability, and exposure data in Aotearoa New Zealand, Progress in Disaster Science, https://doi.org/10.1016/j.pdisas.2021.100213.
Harrison, S. E., Potter, S. H., Prasanna, R., Doyle, E. E., & Johnston, D. (2024). Nurturing partnerships to support data access for impact forecasts and warnings: Theoretical integration and synthesis. International Journal of Disaster Risk Reduction, 104395. https://www.sciencedirect.com/science/article/pii/S2212420924001572
WMO (2021). WMO Guidelines on Multi-Hazard Impact-Based Forecast and Warning Services - Part II: Putting Multi-Hazard IBFWS into Practice. WMO-No 1150. World Meteorological Organization. https://library.wmo.int/records/item/57739-wmo-guidelines-on-multi-hazard-impact-based-forecast-and-warning-services?offset=1
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