Persistent positive anomalies in geopotential height drive enhanced wildfire activity across Europe

Persistent positive anomalies in 500 hPa geopotential height (PPAs) are upper-air circulation patterns associated with surface heatwaves, drought, and consequently fuel aridity, elevated fire weather, and active wildfires. We examined the association between PPA events and surface fire weather and burned area at a pan-European level. Europe-wide, extreme fire weather and wildfires were on average 3.5 and 2.3 times more likely to occur concurrently with a PPA, respectively. PPAs were associated with 43% of pan-European area burned between March and October 2001–2021, and there was a latitudinal increase in the percentage of area burned during PPAs up to 60% over Northern Europe. Burned area was highest in the three days following PPA presence, and fuel moisture indices from the Canadian Fire Weather Index System lagged behind peak PPA strength, demonstrating the role of PPAs in pre-drying fuels. PPAs have been associated with significant wildfire events experienced across Europe, including the 2017 Portugal wildfires, the 2018 UK, Sweden, and Finland wildfires, and the 2021 Greece wildfires. Our findings demonstrate opportunities for developing early warning systems of wildfire danger, having implications for wildfire awareness and preparedness, informing policy, and wildfire management decisions like early mobilisation and resource sharing initiatives within and across Europe.