Developing a risk-based severe weather warning system for New Zealand: Challenges and opportunities

National Meteorological and Hydrological Services (NMHSs) are moving towards communicating weather warnings in terms of the level of weather-related risk or impacts that might occur, rather than the severity of the weather hazard. Two key challenges with this approach are that meteorologists in forecasting offices are (a) often unfamiliar with the local exposure and vulnerability information needed to assess the likely impacts and risk, and (b) generally wary of commenting on matters that are not strictly meteorological. Local exposure and vulnerability information is held by civil protection agencies and other stakeholders. Time constraints in issuing warnings often preclude stakeholder input to determining the level of warning. Some NMHSs use risk matrices to determine the level of warning, incorporating scientists' knowledge of the potential impacts. This approach has challenges, including the lack of expertise of meteorologists in this area, and difficulties in communicating high impact/low probability events. Additionally, issuing risk-based warnings requires a decision on whether the level of risk is relative to all other possible weather-related risk in the country, or whether it should be determined at a regional, community, or individual (life safety) level. Social science research is being conducted in collaboration with Meteorological Service of New Zealand Limited, New Zealand's NMHS, to engage with stakeholders and determine the viability of a risk-based warning approach for severe weather hazards. This presentation will give an overview of preliminary findings, describe a potential solution to these issues that is being investigated, and outline the plan going forward for the remainder of this research.