CLAVERIA, PHILIPPINES (NYTIMES) - Typhoon Mangkhut, which meteorologists called the most powerful storm in the world this year, swept through the northern end of the Philippine island of Luzon, leaving at least 25 people dead and wreaking havoc. It uprooted trees, ripped off roofs, set off landslides and flooded farms and roads.

Yet, amid the suffering, there was also relief that the situation was not much worse. The initial casualty toll was far lower than officials had feared in the days before the storm made landfall early Saturday on the Philippines' largest and most populous island.

But it could be days or weeks before the storm's true human toll is known. It will also take time to assess how much damage was done to the country's prime agricultural region and to the economy. Damage to farms could be extensive - and costly for the nation. The region is the country's largest food producer, and the destruction of crops could lead to food shortages, higher costs and inflation.

From the road above Mr Robert Tumaneng's fish ponds on Saturday, the floodwaters extended as far as the eye could see, with the tips of palm trees and the thatched roofs of wooden shacks barely visible beneath the caramel-coloured water.

"It was shaking like an earthquake," said Mr Tumaneng, 55, a fish farmer in the town of Claveria on Luzon's north coast. "This storm was different because the wind was low to the ground like it was crawling and destroying everything," he said after the storm hit.

The number of confirmed fatalities is almost certain to rise as people begin assessing damage from the typhoon. But if the numbers are limited, it will be, at least in part, a testament to the preparedness of authorities following disastrous storms in recent years.

Determined not to see a repeat of Typhoon Haiyan, which killed more than 6,000 people in the central Philippines in 2013, officials had evacuated more than 105,000 people to temporary shelters before Typhoon Mangkhut hit.

Communications in the disaster zone were hampered by power and mobile service blackouts, and access was difficult in many places because of flooding and road closures, making it hard to evaluate the storm's full effect.

Trees and coconuts were strewed across the roads, which were deserted except for volunteer crews removing debris and the occasional emergency vehicle.

In one community after another, emergency workers reported downed trees and badly damaged buildings. Signs, tin roofs and gates that had been torn free flew about.

"At this stage, it is still too early to understand the full impact of the typhoon," said Ms Gina Maramag, spokesman in the Philippines for the United Nations Office for the Coordination of Humanitarian Affairs. "Early indications suggest that the prompt evacuations made by local authorities have mitigated the impact on civilians."

Among the casualties was a family of four killed when a landslide struck their home in the Cordillera Mountains, south of Claveria, according to a top government official, Mr Francis Tolentino. He spoke in a television interview from the disaster zone on Saturday evening.

Philippines Emergency Response Team that reached the town of Aparri on the north coast reported that some structures were damaged by the storm, including an evacuation centre. But much of the surrounding area had yet to be assessed.

"The northernmost towns of Cagayan are believed to be badly hit and it is still difficult to access these areas as of the moment," said Madel Montejo, a member of that emergency response team. "The people say they need food, water, dry clothes and shelter repair materials."

The typhoon, with wind speeds reaching 170 mph (274kmh) before reaching land, could have caused far more damage if it had hit Luzon farther south and closer to Manila - a megacity of more than 12 million people. The capital was hit by heavy rain and strong winds, with trees uprooted and flooding in some areas.

More than 1,600 families were evacuated after the Marikina River, which runs through part of the city, began rising quickly because of runoff from nearby mountains. Police said the body of a child, about 10 years old, was found floating in the river.

The area of Luzon that the typhoon hit hardest is primarily agricultural and, with more than four million people, is less densely populated than other parts of the country.

"The country has learnt a lot from the Haiyan tragedy, which explains more effective mandatory evacuation and coping measures in place," said Mr Richard Heydarian, a political analyst in Manila. "But the economic costs could be severe."

In Claveria, a town of about 30,000 in Cagayan province, the Antonio family was one that did not evacuate - at first. But at about 1am, when strong winds made them fear for their safety, they moved to the shelter of their of their in-laws' sturdier home.

Mr Marck James Antonio, 24, stayed behind and was struck in the right temple by part of the roof that flew off, leaving a big gash.

"This was the strongest and the worst storm that I've ever experienced in my life," said his mother, Mrs Teresita Antonio, 54. "I was crying because I don't know how I will be able to afford to fix my house." No rescuers have reached the area yet.

In the town of Sanchez-Mira, a dozen miles east, local officials said they had ensured people's safety by pushing them to take shelter at the community hall. Eventually, 271 people complied. Some had to be rounded up by police car.

"Some people didn't want to evacuate their homes but I forced them," said community leader Rewin Valenzuela, 48. "If we didn't make them evacuate, they could have lost their lives. We evacuated everyone to prevent loss of life."