BEIJING -- China's State Flood Control and Drought Relief Headquarters on Tuesday elevated the typhoon emergency response to Level III for Guangdong and Hainan provinces as Typhoon Ragasa, the 18th of the year, approaches landfall.

According to the Ministry of Emergency Management, the powerful typhoon, currently about 640 kilometers southeast of Yangjiang city in Guangdong, over the South China Sea, is expected to make landfall along Guangdong's coast between Zhuhai and Zhanjiang from midday to late Wednesday.

The storm will bring torrential rainfall to parts of Guangdong, Fujian and Zhejiang provinces.

The headquarters had earlier dispatched a work team to assist with preparations.

China has a four-tier emergency response system, with Level I being the most severe response.