Residents and officials in southern China are bracing for the full force of Super Typhoon Ragasa, the most powerful typhoon to hit the region in recent years.

By Tuesday, Guangdong province had upgraded its typhoon alert to Level 1, the highest in a four-tier warning system, as officials declared a “combat-ready” status.

China’s National Meteorological Centre said the typhoon was expected to land between Taishan and Dianbai in western Guangdong, bringing winds of up to 200km/h, rain between 25cm to 45cm (9 to 17 inches) and waves as high as 7 metres (23 feet).

On Wednesday morning, Guangzhou was overcast with heavy cloud cover, but no rainfall was reported downtown areas.

More than 371,000 people have been evacuated across the province while helicopters and drones, 23 ships and 38,000 firefighters remain on standby.

More than 10 cities in Guangdong announced schools, businesses, markets and transport closures, affecting tens of millions of people.

By midday on Tuesday, the southern tech hub of Shenzhen had cancelled 210 departing flights and 319 incoming flights. All buses, taxis, subways and highways were closed by Tuesday evening.

Residents have been stockpiling food, water and even portable phone batteries for the past two days. Businesses have taped their windows, tied down rubbish bins and outdoor chairs, while local governments trimmed trees and checked underground passageways, construction sites and mountainous regions for safety hazards.