HANOI -— Vietnam closed schools, airports, and evacuated thousands of people as it braced for powerful Typhoon Kajiki to make landfall Monday, threatening the country’s northeast with destructive winds and storm surges.

The typhoon downed trees and soaked China’s southern Hainan island on Sunday before moving over the Gulf of Tonkin overnight with sustained wind speeds of 166 kph (103 mph), according to Vietnam’s national weather forecast agency, the equivalent to a Category 2 Atlantic hurricane.

More than 40,000 people had been evacuated in low-lying coastal communities as of Monday morning, according to the state-run VN Express. Residents have been told not to leave their homes between 11 a.m. and 6 p.m. local time, the state Vietnamese News Agency (VNA) reported.

Kajiki is the fifth typhoon to hit Vietnam this year and the most powerful, having sustained its intensity as it churned toward the coast.

Ahead of landfall, Vietnam’s Prime Minister Pham Minh Chinh warned the storm could unleash heavy rainfall, flash floods and landslides especially for the low-lying coastal areas, according to Vietnamese state media.

“This is an extremely dangerous fast-moving storm,” the government said in a statement Sunday night, Reuters news agency reported.

Kajiki is expected to make landfall in the central provinces of Thanh Hoa and Nghe An late afternoon into evening local time, as either a weak typhoon or strong tropical storm. Thanh Hoa is about 166 kilometers (103 miles) south of Hanoi.

Government officials had compared the typhoon to Typhoon Yagi, the most powerful storm to hit the region last year, which devastated Vietnam’s north, killing about 300 people and causing widespread damage to infrastructure, factories and farmland. Yagi made landfall as the equivalent of a Category 4 hurricane, and while Kajiki is weaker, it is still expected to bring destructive winds and threats of flooding.

Residents and business owners have boarded up windows and stacked sandbags outside homes, restaurants and hotels, according to images posted by state media.

On Monday, the country’s Civil Aviation Authority closed two provincial airports in central Vietnam, and Vietnamese airlines canceled or delayed dozens of flights as the typhoon approached, state media reported. Schools in Thanh Hoa were reportedly also closed for two days.

Authorities in the country’s central provinces activated emergency measures on Sunday, which included a plan to evacuate around 587,000 people from Thanh Hoa, Quang Tri, Hue and Danang provinces, banning fishing vessels from leaving shore and securing dams and flood walls, according to VNA.

More than 300,000 military personnel were mobilized with the Navy, Coast Guard and Air Force on standby for rescue operations, the news agency reported.

Storm surges of up to 1.5 meters were forecast with sea levels in some areas expected to reach more than 3.5 meters, and concerns lie with those living on much of the low-lying north-east and central coast.

There are fears that the torrential rain and winds from Kajiki will inundate farms and villages in the storm’s path, destroying crops and killing livestock.

China’s Meteorological Center said the storm will bring heavy rain to 13 provinces in central and northern Vietnam, as well as Laos and Thailand, as it moves inland, with the risk for flash flooding and mudslides increasing. Between 200-400 millimeters of rain is forecast in some regions, with isolated areas exceeding 600 mm.

The Joint Typhoon Warning Center has forecast that Kajiki will weaken quickly over land, dropping to tropical depression strength by early Tuesday.

Typhoon Kajiki brushed past the southern coast of China’s Hainan island and parts of Guangdong province Sunday evening. Known for its sandy beaches, luxury resorts and duty-free shopping, the city of Sanya on Hainan island closed tourist attractions, shuttered businesses and suspended public transport.

Authorities activated emergency responses as heavy rain and strong winds lashed the city and surrounding areas. Video posted on social media from Sanya showed trees toppling onto cars and falling across roads in the gale-force winds, people struggling to stand and, in one clip, a person riding a moped can be seen trapped underneath a fallen tree.

Sanya issued a red typhoon alert on Sunday morning - the highest in China’s color-coded warning system - and raised its emergency response to the most severe level. The alert was downgraded on Monday morning but heavy rains and storms in southern Hainan are expected to continue, Reuters reported. - CNN