Taiwan has put its military units on standby and closed schools and offices across several counties on Tuesday, as the island braces for a powerful typhoon set to make landfall in the next couple days, after bashing the Philippines.

Super Typhoon Krathon, equivalent to a Category 4 Atlantic hurricane, is currently situated in the Bashi Channel in the northern part of the Luzon Strait, between Taiwan and the Philippines. As of 11:30 a.m. local time Tuesday, it had winds of 240 kph (150 mph), according to the Joint Typhoon Warning Center (JTWC).

It is expected to weaken slightly before making landfall near Taiwan’s major port city of Kaohsiung on Wednesday afternoon or Thursday morning local time, as it moves northeast across the island, bringing heavy rains, strong winds and storm surge.

The storm, known locally in the Philippines as Julien, has already lashed the country’s northernmost islands, prompting evacuations and severe flooding in coastal communities. Rainfalls of up to 100-200mm (4-8 inches) have been recorded across the northern Batanes islands.

Nearly 23,000 families in three regions have been affected by the storm, the Philippines’ national disaster agency said Tuesday, according to the Philippine News Agency, as authorities work to assess the damage.

On Tuesday, Taiwan’s president warned of the “catastrophic damage” that the storm could impose on the island and warned “everyone must be particularly vigilant.”

“Typhoon Krathon has intensified into a strong typhoon with strong wind, heavy rain and high storm surge, and it is set to bring catastrophic damage,” Taiwan President Lai Ching-te said on Tuesday during a visit to the Central Emergency Operations Center, which was set up over the weekend to coordinate response measures to the typhoon.

Taiwan generally has a strong track record of responding to major typhoons though remote villages in more mountainous region can be particularly vulnerable to landslides.

Taiwan’s Central Weather Administration (CWA) has issued a sea and land typhoon warning for southern and eastern parts of the island, warning the typhoon could pose a significant threat due to its slow speed and bring torrential rains to parts of the southeast.

In Kaohsiung, the biggest city in southern Taiwan with a population of 2.7 million and a major cargo port, emergency responders have already evacuated 1,690 people from high-risk areas, according to city mayor Chen Chi-mai.

More than 15,000 Taiwanese soldiers are on standby across different parts of the island to assist with evacuation and rescue efforts, Taiwan’s defense ministry spokesman Sun Li-fang told reporters on Monday.

Krathon is set to be the second typhoon to make landfall on Taiwan this year, after Typhoon Gaemi struck the island in July, killing 11 people.

Some train services in eastern Taiwan have already been suspended, and a highway in eastern Taiwan’s Hualien county has partially closed due to landslides, according to transportation authorities.