For the first time in recorded history, two Category 4 hurricanes have hit the continental United States in the same year.
This morning, Hurricane Irma is causing devastation in Florida more than a week after Hurricane Harvey lambasted Texas and parts of Louisiana.
The Saffir-Simpson Hurricane Wind Scale has five levels. Category 4 is considered "major" and causes catastropic damage, with wind speeds reaching 209 to 251 kilometres per hour.
"Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls," the National Hurricane Center explains on its website. "Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months."
Hurricane Irma's winds were reportedly at 225 kilometres per hour in the Florida Keys this morning.
Below, you can see some YouTube videos of what's taking place.