A spell of exceptionally intense precipitation across Türkiye’s Marmara region has broken historic meteorological records, delivering an unprecedented volume of rainfall to the metropolis of Istanbul within a remarkably brief window.

The storm generated localised rainfall figures rarely witnessed in the region's recorded climate history.

Meteorological measuring stations across the Marmara basin recorded extreme cloudbursts that shattered seasonal averages. In several Istanbul districts, precipitation levels exceeded 100 to 130 millimetres per square metre within just a few hours — a volume equivalent to nearly two months' worth of average autumn rainfall hitting the ground at once.

The sudden volume of water overwhelmed municipal drainage networks, causing underpasses, underground passages, and low-lying ground-floor properties to submerge rapidly.

While the entire Marmara region experienced heavy precipitation, Istanbul bore the brunt of the storm's impact, with several neighbourhoods experiencing critical damage.

In response to the escalating situation, central authorities in Ankara deployed state resources to coordinate emergency management and relief operations across the Marmara region.

The Disaster and Emergency Management Authority (AFAD) was immediately mobilised to direct field operations, dispatching high-capacity water evacuation pumps, search and rescue personnel, and amphibious vehicles to support Istanbul's emergency teams.

National meteorological authorities issued high-level weather alerts urging citizens to avoid unnecessary travel and remain indoors as municipal teams worked around the clock to clear debris and pump out submerged infrastructure.