How Irma’s odd track saved Miami and Key West from even worse.

Let’s face it; Hurricane Irma was bad and much of Florida is a complete mess. But quirks in Irma’s final path during the 48 hours before Florida landfall saved Miami and Key West from the worst case scenario of a direct hit.

Here’s why Irma’s eventual track was a lucky break for some of Florida’s biggest cities.

Cuba landfall

Irma’s eyewall raked Cuba’s northern coast and made landfall there. That put the southern sector of Irma over Cuba’s mountainous terrain. The interaction with Cuba’s mountains helped weaken Irma from Category 5 to Category 3.

After bouncing off Cuba, Irma’s eyewall became ragged and wobbly at times. Irma never fully recovered her Category 5 intensity after that.


Miami: Lucky shift west

Many of the most reliable forecast models had Miami in Irma’s cross-hairs for several days before landfall. Even earth’s best weather forecast model portrayed a direct hit on Miami and Florida’s east coast as late as early Friday morning.

Forecast tracks correctly shifted Irma’s path westward in the 48 hours leading up to landfall.

The westward shift away from Miami in the 48 hours before landfall was a godsend for Miami and Florida’s east coast. Eve with the westward shift, Miami looked like this as Irma’s spiraling bands and storm surge ripped through.

Had Irma’s eyewall put a direct hit on Miami the impacts would have been nothing short of catastrophic. Simply out; Miami got lucky with Irma.

Key West: Eyewall near miss

As Irma turned north from Cuba into the Florida Straits, the biggest question was where would the eye make landfall in the Keys? Fortunately for Key West, the core of Irma’s northern eyewall would pass just just 20-30 miles east of Key West.

That path probably saved Key West from the devastating impacts from massive storm surge we are only now beginning to see in the islands to the east.

Even though the eyewall core passed east of Key West, many communications have been cut to the island. Flood and wind damage is significant.

Marathon Key: Complete over-wash?

Storm surge appears to have been highest in the central Keys. Here’s damage near Marathon Key.

Inland curve

Irma’s westward shift was not good news for Naples and Fort Myers where she made landfall. Damage there is extensive, but this less populated area will mean a lower overall storm toll than a direct hit in places like Miami.

Tampa: Irma moves inland

Many forecast models and the offical NHC forecast track suggested Irma would ride the Florida’s west coast toward Tampa. Instead Irma moved straight north, largely bypassing Tampa to the east. That was another lucky turn for a major Florida city.

Record Jacksonville flooding

Tampa’s gain appears to have been Jacksonville’s loss. The eastward track and Irma’s sheer size pumped surge and heavy flooding rains into Jacksonville.

Flood levels on the St. John’s River reached record levels.

So Irma has produced extensive surge, flood, and wind damage as expected in Florida. The patchwork damage pattern is typical of hurricanes. Still, Irma’s track likely saved places like Miami and Key West from an even bigger catastrophe.