Typhoon Yagi kills dozens in the Philippines, China, and Vietnam.

Typhoon Yagi, which was Asia's strongest storm of the year, was reduced to a tropical depression on Sunday after killing scores of people in the Philippines, China's Hainan province, and northern Vietnam, according to early reports.

Although the downgrade was announced on Sunday, Vietnam's meteorological agency issued a warning about the continued risk of flooding and landslides as the storm—which is the strongest to hit the nation in decades—moves west.

In Hanoi, the capital of Vietnam, Yagi cut off power and communications on Saturday, resulting in widespread flooding, the felling of thousands of trees, and damage to homes.

The 8.5 million-person city of Hanoi has seen at least three fatalities as a result of the storm, according to the government, though these numbers are preliminary. Reports state that as of now, 14 people have perished in Vietnam, four of whom were involved in a landslide in the province of Hoa Binh, which is located roughly 100 kilometers (62 miles) south of Hanoi.

According to state media, a 53-year-old motorcyclist in the northern province of Hai Duong was killed when a tree fell on him. Twelve people were reported missing at sea near the coastal city of Halong; at least one body has been found there. Rescue efforts are scheduled to begin on Sunday, weather permitting.

Four people have lost their lives as a result of Yagi on the southern Chinese island of Hainan, local authorities have reported. The first nation that Yagi struck after forming last week was the Philippines, where the civil defense office announced on Sunday that 22 people were still missing and that the death toll had increased from 16 to 20.

Hazard of sudden flooding

Yagi caused waves as high as 4 meters (13 feet) in coastal provinces after it made landfall in Vietnam on Saturday afternoon, the government said. This resulted in prolonged power and telecommunication outages that complicated damage assessment.

The coastal province of Thanh Hoa and the northern mountainous areas were among the areas where the meteorological agency continued to issue warnings about the "risk of flash floods near small rivers and streams, and landslides on steep slopes in many places."

On Sunday morning, Hanoi saw a relative return to calm as officials hurried to clear the streets of fallen trees that were strewn throughout the city center and other neighborhoods.

 "The city has been devastated by the storm.

Trees toppled over people's homes, vehicles, and pedestrians in the street, according to 57-year-old Hoang Ngoc Nhien, a resident of Hanoi.

The busiest airport in northern Vietnam, Noi Bai International Airport in Hanoi, reopened on Sunday after closing early on Saturday.

According to emergency response authorities cited by state-run Hainan Daily, preliminary estimates in Hainan indicated significant economic losses and widespread power outages.