Hurricane Irma, the most powerful Atlantic Ocean hurricane ever recorded, made landfall over Barbuda at 2 AM Wednesday morning. The Category 5 storm threatens numerous Caribean islands, including St. Martin, St. Kitts, the Virgin Islands, Hispaniola, and Cuba. Moving at 185 miles per hour, Irma is also rapidly heading towards Puerto Rico, with the eye of the hurricane 130 miles from San Juan as of 7:30 AM.

A United States territory with a population of 3.4 million, Puerto Rico stands to bear massive devastation if hit with the brunt of the hurricane. According to the National Weather Service, a hurricane warning is in effect for all of Puerto Rico and the U.S. Virgin Islands for at least the next six hours.

The hurricane is expected to predominantly hit Northeast Puerto Rico, which includes the territory’s capital, San Juan. Early Wednesday morning, the National Weather Service warned that the current threat to life and property was “extreme”:

“Remain braced against the reasonable threat for major hurricane force wind greater than 100 mph of equivalent Category 3 intensity of higher. To be safe, efforts should fully focus on protecting life. Properties remain subject to devastating to catastrophic wind impacts. Now is the time to urgently hide from the wind. Failure to adequately shelter may result in serious injury, loss of life, or immense human suffering.”

National Weather Service image of Puerto Rico at 9:53 EST.

It has been a century since a Category 5 storm has made landfall in Puerto Rico. According to The New York Times, Puerto Rican officials are concerned that the storm could shut down the island’s electrical grid for months. Puerto Rico’s Governor, Ricardo Rosselló, said in a news conference on Tuesday that “[we] have to prepare for an event that we have never experienced here.”

Meanwhile, while the eye of Irma draws near, the island has already begun to experience heavy rainfall and tropical winds.

A Category 5 hurricane is classified according to the Saffir-Simpson Hurricane Wind Scale, which uses a scale of one to five, where five is the strongest possible. The scale is based on the hurricane’s sustained wind speeds: Categories 1 and 2 are dangerous, and Category 3 constitutes a major storm. To be a Category 5 hurricane, winds must reach speeds of 157 miles per hour or higher, at which point catastrophic damage is likely.

“A high percentage of framed homes will be destroyed, with total roof failure and wall collapse.” the National Hurricane Center explains. “Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.”

There is a chance that the eye of the storm will hit just north of land, which will slightly diminish the storm’s potential devastation. While Puerto Ricans prepare, residents of Florida, Georgia, and the Carolinas are preparing for the possibility of Irma making landfall in the U.S., which could occur this weekend. On Monday, Florida’s governor Rick Scott declared a state of emergency for the entire state, while President Donald Trump declared a state of emergency for Florida, Puerto Rico, and the U.S. Virgin Islands on Tuesday.