Typhoon Megi had sustained winds of 140 miles (225 kilometers) per hour and gusts of 162 mph (260 kph) by nightfall but could strengthen as it moves west at 14 mph (22 kph) over the Philippine Sea. Forecasters said it’s expected to slam into Cagayan province Monday morning.

With its ferocious wind, Megi has become the strongest typhoon to threaten the country in four years, government forecasters say. A 2006 howler with 155-mph (250-kph) winds set off volcanic mudslides that buried entire villages, killing about 1,000 people.

Weather officials issued the highest of a four-tier public storm alert for Cagayan and nearby Isabela province, warning of pounding rains and fierce wind that could significantly damage agriculture, residential areas, power and communications. They urged all outdoor activities to be cancelled and advised one family member to stay awake overnight for any contingency.

Thousands of military reserve officers and volunteers were on stand by, along with helicopters, including six Chinooks that were committed by U.S. troops holding war exercises with Filipino soldiers near Manila, said Benito Ramos, a top disaster-response official.

Rescue boats and thousands of food packs have been pre-positioned near vulnerable areas, he said, adding that schools along the typhoon’s path would be closed.

The weather bureau has warned fishermen and travelers to stay out of harm’s way.

“This is like preparing for war,” Ramos, a retired army general, told The Associated Press. “We know the past lessons and we’re aiming for zero casualties.”

An angry President Benigno Aquino III fired the head of the weather bureau in July for failing to predict that a typhoon would hit Manila. More than 100 people were killed in Manila and outlying provinces by that storm.

Authorities planned to start evacuating residents Sunday in and near areas where storm surges, flooding and landslides could happen. Dozens of families voluntarily moved out of their homes to safer ground Saturday in mountainous Isabela, Ramos said, estimating at least a few thousands of people have evacuated from their homes there and in Cagayan by Sunday night.

In nearby Cagayan, a vast agricultural valley crisscrossed by rivers and creeks, authorities have ordered villagers to move out of high-risk neighborhoods in 12 coastal towns.

“If nobody will budge, we may carry out forced evacuations,” said Bonifacio Cuarteros of the Provincial Disaster Risk Reduction and Management office.

Farmers in Cagayan, a rice- and tobacco-producing region of more than 1 million people about 250 miles (400 kilometers) northeast of Manila, have been warned to harvest as much of their crops as possible before Typhoon Megi hits or risk losses, Cuarteros said, adding the typhoon would hit amid the harvest season.

With its current course and speed, the typhoon is expected to barrel across the northern tip of Luzon island then blow into the South China Sea late Monday toward northern Vietnam or southern China, weather bureau official Nataniel Servando said.

China’s National Meteorological Center issued its second-highest alert for potential “wild winds and huge waves,” warning vessels to take shelter and urging authorities to brace for emergencies, the state-run Xinhua News Agency reported Sunday.