after becoming a hurricane on September 6, Carla curved northward in the northwestern Caribbean Sea. At 1200 UTC on September 7, the storm intensified into a Category 2 hurricane while located east-northeast of Cozumel, Quintana Roo, Mexico (actual use of the Saffir-Simpson Hurricane Wind Scale, which was developed in 1971, was not in effect). Shortly thereafter, Carla crossed the Yucatán Channel and entered the Gulf of Mexico. A strong high-pressure area forced Carla to resume its original northwesterly course. Early on September 8, the storm strengthened into a Category 3 hurricane while located just north of the Yucatán Peninsula. Thus, Carla was the third major hurricane of the season. Carla was upgraded to a Category 4 hurricane early on September 10, while approaching the Gulf Coast of the United States. Operationally, at 0000 UTC on September 11, Carla strengthened into a Category 5 hurricane while located in the northwestern Gulf of Mexico. Six hours later, the storm reached its maximum sustained wind speed of 175 mph (280 km/h). However, a 2018 reanalysis concluded that Carla did not reach Category 5 intensity, and in fact only had maximum sustained winds of 145 mph (230 km/h), and this has been officially incorporated into HURDAT. Late on September 11, Carla reached its minimum barometric pressure of . Later that day, the storm struck Matagorda Island, Texas (seven miles south of Port O'Connor) with winds of 145 mph (230 km/h). Carla rapidly weakened inland, and degenerated to a Category 2 hurricane on September 12, while passing just east of Port Lavaca. Six hours later, the storm was downgraded to a Category 1 hurricane near Shiner, shortly before being downgraded to a tropical storm between Taylor and Coupland. Beginning late on September 12, the storm curved just east of due north. After reaching Oklahoma early on September 13, Carla transitioned into an extratropical cyclone while located over rural Johnston County. The extratropical remnants of Carla moved rapidly northeastward and brought heavy rainfall to some areas of the Great Plains and Midwestern United States. By September 14, it entered Canada near Sault Ste. Marie, Ontario. It then continued swiftly northeastward across Ontario, Quebec, and Labrador, before the remnants dissipated over the Labrador Sea on September 17. Preparations Occurring a year after Hurricane Donna, officials in the Florida Keys took precautions to brace for potential impact from the storm. The United States Navy flew their planes out