(CNN) -- The world's strongest storm of the year so far plowed across the northern Philippines on Monday, killing at least one person and leaving 20 fishermen missing.
Packing winds as strong as 200 kilometers per hour (124 mph), Typhoon Utor made landfall early Monday on the east coast of the Philippine island of Luzon, damaging hundreds of houses.
"It's the strongest typhoon we've had so far on the planet this year," said CNN International meteorologist Samantha Mohr. "So that gives you some idea of the magnitude of this system."
Utor, known in the Philippines as Labuyo, churned west-northwest over Luzon, dumping heavy rain on the island's hilly terrain and bringing the risk of landslides. It weakened as it moved over land, and by Monday afternoon, it had begun to head out into the South China Sea.
Aid groups in the Philippines, which had been preparing for the storm's arrival for several days, said they were only just beginning to assess the situation on the ground in the hardest-hit areas.
"There's a high risk that part of the population may get isolated because of landslides and difficulty moving around," said Anna Lindenfors, country director for Save the Children in the Philippines.
The country's National Disaster Risk Reduction and Management Council reported one death in the province of Benguet on Monday afternoon.
Twenty fishermen who had headed out to sea before the storm's arrival remained unaccounted for, the agency said. But dozens of others who had initially been reported missing had returned home safely, it said.
The agency reported damage to 673 houses in the province of Aurora, where the storm made landfall.
The typhoon destroyed nearly 80% of the infrastructure in Casiguran, a town that lay in Utor's path across the province, CNN affiliate ABS-CBN reported.
The storm tore apart rickety houses and ripped the roof off a local hospital, the local broadcaster said, showing images of flattened homes buried under fallen trees.
Situated near an area of the Pacific Ocean where typhoons form, the Philippines regularly suffers severe storm damage.
An average of 20 typhoons hit the Southeast Asian country every year, and two or three of those cause serious damage, according to Plan International, an aid and development organization.
Utor is expected to pick up more strength over the warm waters of the South China Sea over the next day or so before making landfall on the southern coast of China on Wednesday.
CNN's Anjali Tsui contributed to this report.