By Paul Homewood
Regular readers will know that I have often queried the windspeeds claimed nowadays for hurricanes.
The problem stems from the fact that in the past windspeeds were estimated on the basis of central pressure. Certainly anemometers would never have been able to withstand the strongest winds; nor would they have been likely to have been in the exact location where winds were strongest.
In recent years however winds are estimated using satellite and aircraft dropsonde data.
The problem, however, is that consistently we find that windspeeds and central pressure do not reconcile in the same way as they did in the past.
Idalia came ashore with sustained winds, so we are told, of 125 mph, and a central pressure of 949 MB.
The chart below plots the windspeeds of all US landfalling hurricanes with central pressure of 948, 949 and 950 MB at landfall:
As is instantly obvious, nearly all those historical hurricanes had estimated winds of between 100 and 115 mph. The oddity is the 1926 hurricane which was said to be only 75 mph, but had central pressure of 949 MB.
But sticking out like a sore thumb is Idalia, with winds of at least 10 mph higher than any others. This clearly cannot be right.
If it is true that Idalia really did have 125 mph winds, then clearly all of those hurricanes in the past have been grossly underestimated.
The figure of 125 mph came in this instance from a Hurricane Hunter aircraft, but it is worth noting that Keaton Beach, where landfall was made, the weather station there only recorded 61 mph:
I’ll leave you with one last thought.
Two hurricanes in the 1920s utterly devastated Florida:
- The 1926 Great Miami Hurricane
This storm razed much of Miami to the ground, and is reckoned to be the costliest Atlantic hurricane of all time, at current prices, even more so than Katrina.
But according to the US National Hurricane Center, it also made landfall with winds of 125 mph just like Idalia, despite much lower central pressure of 930 MB.
- 1928 Lake Okechobee
Two years later, Florida was hit by another catastrophic hurricane, which had already decimated Guadeloupe, destroying nearly every building there and killing over 1000 people.
Coastal South Florida saw catastrophic damage as well, the heaviest in Palm Beach County. Towns greatly affected were Jupiter, Delray, Lake Worth, Pompano, West Palm Beach and Palm Beach, all of which were impacted by the hurricane’s 3 m (10 ft) storm surge. In West Palm Beach, 1,711 homes were destroyed and 6,363 more were damaged. The greatest devastation occurred, however, along the south shore of Lake Okeechobee. There, the 3 m (10 ft) surge washed over the lake’s 1.5-2.4 m (5-8 ft) dikes and flooded an area 120 km (75 mi) wide. At Belle Glade, one of the hardest hit areas, the floodwaters rose to a height of 2.1 meters (7 ft) at a rate of about 25 mm (1 in) per minute. In all, between 2,500 and 3,000 people died making this hurricane the second deadliest hurricane in U.S. History after the 1900 Galveston Hurricane. Total damages from the storm amounted to $100 million (1928 USD) across the Caribbean and the US.
It is interesting that at the time windspeeds at landfall were estimated at 150 mph. But since this has been downgraded by the National Hurricane Center to 125 mph, despite central pressure of 929 MB.
Was Idalia truly as strong as these two storms? Did they all have 125 mph winds?
It is clear that the damage wrought by Idalia was not on the same scale as the 1926 and 1928 ones. Indeed most resulted from the storm surge, which we know was much lower. There’s a CBS video from Cedar Key, which was hit hardest by Idalia, and which shows may buildings barely damaged at all.
This together with the central pressure data tells us that it is absurd to claim that Idalia was as strong.