Intense rainfall overwhelms Barcelona and eastern Spain
A slow-moving Mediterranean low, combined with abundant moist air and strong convective instability, produced exceptionally intense rainfall across Barcelona and eastern Spain on 3–4 October 2026. In places, rainfall totals exceeded 200 mm, with 3 October the wettest day in Barcelona's observed record.
Flooding was initially dominated by intense rainfall overwhelming urban drainage and causing surface water flooding, but flashy river catchments in the steep near-coastal terrain, such as the Besòs River, also flooded. The event fits the region’s established pattern of severe autumn Mediterranean flash flooding, but stands out for the exceptional rainfall recorded within Barcelona itself.
Relevant comparisons include the October 1987 rainfall record at El Prat, Storm Gloria in January 2020, and, most significantly, the 1962 Vallès disaster, when about 200 mm fell in two hours and steep ephemeral tributaries of the Besòs and Llobregat rivers produced catastrophic flash floods. The 2026 event was far less deadly, but it highlights the continued vulnerability of the region to extreme short-duration rainfall.
JBA has produced an indicative footprint for the event, based on its stochastic Global Flood Event Set. Download it via our Client Portal or request a copy by emailing eventresponse@jbarisk.com.
We will update the footprint and this report with further information about the event in the coming days.
