Michael of­fi­cially stronger than Ka­t­rina at land­fall


Hur­ri­cane Michael was a storm for the record books, and by one mea­sure­ment was more pow­er­ful at land­fall than no­to­ri­ous mon­sters such as Ka­t­rina or An­drew.

When mea­sured by its baro­met­ric pres­sure of 919 mil­libars, Michael was the third-strong­est hur­ri­cane to make land­fall in the USA, ac­cord­ing to Colorado State Univer­sity me­te­o­rol­o­gist Phil Klotzbach.

A mil­libar is how me­te­o­rol­o­gists de­ter­mine baro­met­ric pres­sure. The lower the mil­libar num­ber, the stronger the storm.

Michael trails only the “La­bor Day” hur­ri­cane (892 mil­libars) that bat­tered the Florida Keys in 1935 and Hur­ri­cane Camille (900 mil­libars), which slammed into the Gulf Coast in the sum­mer of 1969.

Rather than wind speed, baro­met­ric pres­sure should be con­sid­ered the best way to mea­sure a hur­ri­cane’s strength, Der­rick Herndon, an at­mo­spheric sci­en­tist at the Co­op­er­a­tive In­sti­tute for Me­te­o­ro­log­i­cal Satel­lite Stud­ies, told Na­tional Ge­o­graphic.

A study last year in Na­ture Com­mu­ni­ca­tions said, “Pres­sure bet­ter ex­plains his­tor­i­cal eco­nomic dam­ages than does max­i­mum wind speed.”

That’s be­cause cen­tral pres­sure com­bines wind speed and storm size, the study said.

At land­fall, Hur­ri­cane Ka­t­rina was mea­sured at 920 mil­libars. Be­cause Ka­t­rina flooded New Orleans, killing more than 1,000 peo­ple, it will be con­sid­ered a more dev­as­tat­ing and de­struc­tive storm than Michael, which pri­mar­ily hit a lightly pop­u­lated area.

When mea­sured by sus­tained wind speed at land­fall – which was 155 mph near Mex­ico Beach, Florida – Michael drops to fourth place be­hind the hur­ri­canes in 1935 and 1969 and 1992’s Hur­ri­cane An­drew, Klotzbach said.

The 1935 hur­ri­cane hit with winds of 184 mph, Camille’s winds were

173 mph, and An­drew roared ashore into south Florida with winds of

166 mph.

The well-known, 47-year-old Saf­firSimp­son scale of hur­ri­cane in­ten­sity – with its fa­mil­iar Cat­e­gories from 1 to 5 – mea­sures only wind speed. Those three hur­ri­canes (La­bor Day 1935, Camille and An­drew) re­main the only Cat­e­gory 5 hur­ri­canes to hit the United States.

A Cat­e­gory 5 hur­ri­cane has winds of at least 157 mph. Michael missed join­ing that in­fa­mous level by only 2 mph.

Whether mea­sured by wind speed or baro­met­ric pres­sure, how­ever, both of those read­ings may still miss the mark of a hur­ri­cane’s power.

For ex­am­ple, while Michael’s Cat­e­gory 4 rat­ing ac­cu­rately con­veyed its de­struc­tive power, Hur­ri­cane Florence’s Cat­e­gory 1 land­fall last month was an ex­am­ple of the scale’s lim­i­ta­tions. The scale does not take heavy rain – and the re­sult­ing in­land flood­ing – into ac­count.

Wa­ter, whether storm surge from the ocean or flood­ing from heavy rain, of­ten ends up be­ing much more deadly and de­struc­tive than the wind of a hur­ri­cane.

Florence killed dozens of peo­ple and caused tens of bil­lions of dol­lars of dam­age in the Caroli­nas in Septem­ber.


Mike Lind­sey, left, and his son-in-law Chris Allen in­spect the dam­age to El­e­gant En­deav­ors An­tique Em­po­rium in Panama City, Fla.

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