Rescuers on boats in China’s flood-hit Guangdong province raced to evacuate trapped residents, carrying some elderly people by piggyback from their homes and deploying helicopters to save villagers caught in landslides.

Situated in the densely populated Pearl River Delta, the province once dubbed the “factory floor of the world” is prone to summer floods, and over the years, has erected strong defenses against the disruptive effects of flooding.

But since Thursday, Guangdong has been battered by unusually heavy, sustained and widespread rainfall, with powerful storms ushering in an earlier-than-normal start to the region’s annual flooding season.