‘Where oh where is the data?‘: Identifying data sources for hydrometeorological impact forecasts and warnings in Aotearoa New Zealand

Abstract Early Warning Systems are a key component to building preparedness and response capacities to hydrometeorological hazards that continue to affect people worldwide. Notable historic events have revealed gaps in current hazard-based warning systems. Impact Forecasts and Warnings (IFWs) have been proposed to fill these communication gaps by re-centring the warning thresholds and language around the consequences, or impacts, of the hazard(s), rather than just the physical characteristics. However, research has shown that implementing IFWs requires not just hazard data, but also data on impacts, vulnerability, and exposure to understand the risk of impacts. Using Grounded Theory Methodology, we conducted a series of interviews with users and creators of hazard, impact, vulnerability, and exposure (HIVE) data to identify data sources and understand how these data collected and created to support the implementation of IFWs. We focus the study on the New Zealand context to support the country's efforts towards implementing IFWs. Our findings indicate that many of sources for HIVE data exist that are collected for other uses (such as for response efforts for disaster and emergency events, and for research) and have relevant application for IFWs. Our findings further suggest that priorities, motivation, and interest within organisations influence how well data is collected. Moreover, agencies tend to prefer official data, but official data has limitations that unofficial data may address, such as timeliness. To that end, a tension exists between the timeliness and trustworthiness of data needed for emergency response and warnings.