COLUMBUS (WCMH) — Irma initially made landfall Sunday morning about 9:10 a.m. at Cudjoe Key, Florida, in the lower Florida Keys, as a Category 4 hurricane, with maximum sustained winds of 130 mph. This is the first time two Category 4 hurricanes have made landfall in the same season, following Hurricane Harvey’s collision with the Texas coastline on August 25.
While Harvey dawdled for several days over southeast Texas, dumping as much as 30 to 50 inches of rain in the Houston area, including a U.S. continental record rainfall of 51.88 inches at Cedar Bayou, inland wind gusts were not as strong as those generated by Hurricane Irma.
The Ohio State University Geography Department has teamed up with Texas A&M and the University of Michigan to produce a model that projects power outages caused directly by the impact of hurricane-force wind gusts.
Dr. Steven Quiring at Ohio State said, “Our model predicts that upwards of 9 million people will lose power due to the effects of the wind, the saturated soil conditions, and trees falling on power lines. Hurricane Irma is a large storm with a powerful wind field, unlike Harvey, where many of the power outages were rain-driven, and associated with the massive inland flooding
The OSU computer model has accurately predicted power losses within 10 percent during recent hurricanes such as Sandy (Oct. 2012) and Matthew (Oct. 2017).
Irma will go down in the record books among the greatest storms ever seen in the Atlantic basin, occurring during the height of the Atlantic hurricane season, which extends from mid-August to mid-October, and peaks on September 10-11. The storm’s peak 1-minute sustained wind of 185 mph for 37 hours over the open Atlantic established a new intensity record, according to Colorado State University hurricane expert Dr. Philip Klotzbach. The only stronger Atlantic hurricane was Hurricane Allen (190 mph) in 1980, in the Gulf of Mexico.
Memorable storms such as Hurricane Wilma (2005), Gilbert (1988) and the Florida Keys Hurricane (1935) also brought sustained winds of 185 mph, but not for the duration of Irma. Irma also produced the most Accumulated Cyclone Energy (ACE)—a measure of wind energy—for any tropical cyclone in the Atlantic since the inception of the satellite era in 1960.
The central pressure of 914 millibars (27.0 inches) also established a record for any Atlantic basin beyond the Gulf of Mexico and Caribbean Sea. Irma’s pressure at landfall in the Florida Keys Sunday morning of 929 millibars (27.43 inches) is the lowest for any storm making a U.S. landfall since Katrina in 2005 (27.17 inches), and the strongest to hit Florida since Andrew in 1992 (27.23 inches). Irma is the second Category 4 hurricane to make landfall in the U.S. in 16 days, something that has not happened in the same season on record. Irma ranks seventh among all U.S. landfalling storms in the category of lowest pressure, which equates to wind speed.
On Sept. 8, both Irma and Hurricane Jose had sustained winds of at least 150 mph—the first time there have been two such powerful storms at the same time in the Atlantic basin.