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.