Typhoon Noul will dump heavy to torrential rains across much ​of southern China for two days, authorities said, after sweeping ‌the province of Guangdong and neighbouring Hong Kong with gale-force winds, following landfall on Sunday.

China declared its highest alert for flash floods in several provinces as ​the year’s strongest typhoon forced the relocation of more than 700,000 ​people in Guangdong, authorities said.

The year’s 12th tropical cyclone ⁠and China’s third this month, Noul, which means the glow of ​sunrise or sunset in Korean, struck the coast of Huidong county at ​about 3.50am, provincial officials said.

It is expected to bring strong winds and heavy rain to nearby provinces such as Jiangxi and Hunan as it moves inland, state ​broadcaster CCTV said, with the rains likely to persist until Tuesday.

Extremely ​heavy to exceptional downpours are expected to lash some areas, including the province of ‌Fujian, ⁠as the National Meteorological Centre forecast heavy to torrential rain from Sunday until Monday morning across much of China’s south.

Authorities urged local governments to pay special attention to flood-prone areas such as zones of mountains ​and rivers, building ​sites, valleys, and ⁠bridges.

The typhoon is weakening as it moves inland, Hong Kong’s Observatory said, though southwesterly gales pounded parts ​of the Asian financial hub, where authorities downgraded the ​typhoon signal ⁠to No. 3 from No. 8 by afternoon.

Overnight, the storm had passed within 80 km of Hong Kong.

Hong Kong airport authorities said flights ⁠will ​gradually begin resuming on Sunday afternoon, after ​having been mostly suspended for more than 12 hours.