Co-Occurring British Flood-Wind events (1980-2080) and Potential Large-Scale Drivers

Oral Presentation

In wintertime, infrastructure and property in NW Europe are threatened by multiple meteorological hazards, and it is increasingly apparent that these exacerbate risk by tending to co-occurring in events that last days to weeks. Impacted by Atlantic storms, Great Britain (GB) is a sentinel location for weather that later tracks into NW Europe. A recent, dramatic storm sequence (Dudley, Eunice, Franklin) demonstrated the need for a multi-hazard view by bringing a mixture of damaging and disruptive extremes including extreme winds and flooding over 7-10 days in Feb 2022. This work uses a stakeholder inspired, event-based approach to jointly consider these two hazards. A wind event set (n = 3,426) is created from the 12km regional UK Climate projections (1981-1999, 2061-2079) to match previously created high-flow events (Griffin et al, 2023). Then, the two hazards’ time-series are merged using windows up to a maximum size (Dt = 1-180 days) positioned to maximize the size of the largest events’ impact. The uplift in occurrence of the events due to inter-hazard dependency is greatest for the largest events and shorter time windows (Dt = 3 - 21 days), and potential drivers of co-occurrence in the multi-hazard sequences (e.g. jet stream position/strength) are examined.