A4alerts: Design and implementation of a mobile device app for a community-based Site-Specific Early Warning System (SS-EWS) in Catalonia, Spain

<p>Significant progress has been made in the capability and accuracy of forecasting extreme rainfall events and their associated impacts. However, damages remain high and will continue to rise unless immediate actions are taken to support communities in decreasing the impacts of upcoming extreme weather-induced events. In this context, innovative technological tools can help to quickly disseminate relevant impact-based warning information and trigger appropriate self-protection actions based on the local vulnerability and exposure for effective disaster risk reduction. &#160;For this purpose, a mobile app named &#8220;A4alerts&#8221; has been designed in this research. &#160;</p><p>The tailor-based A4alerts app communicates impact-based warnings for vulnerable locations within high-risk areas (SSWs) generated by a community-based site-specific early warning system (SS-EWS). Based on a participatory approach with community stakeholders, the SS-EWS blends meteorological information coming from radar-based nowcasting, numerical weather prediction models and local risk information to trigger the SSWs disseminated via the A4alerts app. In addition to communicating the active warnings in the area, the app lists the available actions recommended to mitigate and reduce the potential local impacts for each warning level based on pre-approved self-protection plans. Furthermore, users can send geotagged photos and information through the A4alerts app to validate the events and their impacts.</p><p>The A4alerts app has been implemented and tested for selected vulnerable points in cities across Catalonia, Spain. Its capabilities and design have been improved following an iterative approach with end-users to incorporate their feedback and suggestions. Finally, the configuration of the A4alerts app allows it to be easily implemented and exported to new cities to help communities be prepared in times of climate emergency.</p>