Hurricane Michael’s intensity being revealed
at Mexico Beach had reached 15.55 feet, half a foot higher than the previous estimate. If you add the waves on top of the surge, the water level here reached 20.6 feet, or close to the height of a two-story building.
That’s what people in the hurricane business call “The Big One.” The term has nothing to do with physical scale — Michael was averagesized. But it was unusually violent, among the four mostintense hurricanes to hit the mainland United States since recordkeeping began in 1851.
“It might be the severest hurricane to hit the U.S. for as long as I’m still alive,” said storm chaser Josh Morgerman, 48, who has been in 45 tropical cyclones and survived the eye of Michael in a disintegrating Holiday Inn Express in Callaway, Florida, an eastern suburb of Panama City.
Mike Brennan, chief of the hurricane specialist unit at the National Hurricane Center, said Hurricane Michael was violent in two ways.
“You had the violence of the winds, the Category 4 winds in the eyewall there, but then you had the violent storm surge that was obviously powerful enough to wipe buildings off their foundation,” Brennan said.
The unlucky people of Mexico Beach suffered both Concrete blocks remain from what once were buildings in Mexico Beach, Fla., after Hurricane Michael roared through a month ago. the maximum winds and the maximum storm surge — the rise in ocean water above normally dry land that the storm plows ashore. In this violent zone, propped against the storm’s calm eye, the forward speed of the hurricane adds to the speed of its counterclockwise circulation. The overlap maximizes the surge.
In a storm as intense as Michael, the eyewall’s winds are equivalent to an EF3 tornado, strong enough to destroy solidly constructed homes and lift vehicles off the ground. The extreme wind damage in Panama City, on the left side of the eyewall, raises the possibility that Michael generated hurricane “mini-swirls,” which are like tiny tornadoes, roughly the diameter of a couple of houses, and can create momentary wind speeds in excess of 200 mph.
Government scientists are still trying to take the measure of the historic storm. Although Michael was officially a Category 4 hurricane, with 155 mph sustained winds when it made landfall, that could be revised upward, to Category 5 — 157 mph and higher — in the ongoing National Hurricane Center analysis.
Every hurricane has a different footprint. Florence, for example, hit the Carolinas in September as a broad, soggy Category 1 hurricane moving at a glacial pace and triggering record flooding. Michael dropped modest levels of rain but was a speed demon.
Michael hit the coast moving 14 mph toward the northnortheast and accelerated to 17 mph. The eye remained well defined, with an eyewall functioning like a lawn-mower blade long after Michael made landfall.
That led to one of Michael’s most stunning features: It stayed a hurricane far inland. It was still a Category 3 hurricane in southwestern Georgia, the strongest storm to hit that state since 1898.
Not until Michael was about 30 miles from Macon, in the center of the state, did the sustained winds drop to the point where Michael was officially just a tropical storm.
Scientists believe climate change might be supercharging such storms, which in recent years have often intensified with unusual speed. Michael was a prime example, making landfall as a monster just three days after it was considered Tropical Depression 14 down near the Yucatan.
“Florence was certainly a bigger storm, in terms of the broader windfield, but Michael was a more powerful hurricane, because of its much lower central pressure,” Brennan said.