MANILA, Philippines — The National Aeronautics and Space Administration (NASA) said it’s an “unusual sight” that four storms churned simultaneously in the Western Pacific Ocean, bringing worries to Filipinos in Luzon, this month.

Citing the Japan Meteorological Agency, it said this is the first time since records began in 1951 that so many storms co-existed in the Pacific basin in November.

“Four storms swirled in the basin, many of which set their sights on the storm-ravaged Philippines,” it said.

NASA said Typhoon season in the West Pacific stretches across the entire year, but most storms form between May and October. November typically sees three named storms, with one becoming a super typhoon, based on the 1991-2000 average.

The Philippines has been reeling from a string of storms since late October, mostly bringing strong rains and causing flooding in the island of Luzon.

Severe Tropical Storm Kristine wreaked havoc in Bicol Region from October 20 to 25. The next day, Super Typhoon Leon entered the Philippine Area of Responsibility. Authorities report that the combined effects of the strong cyclones led to the deaths of at least 150 people.

Typhoon Marce, Typhoon Nika, and Typhoon Ofel soon followed.

The latest storm to enter the country is Ofel, bringing rains in the area of Cagayan.