Hurricane Irma Hits Florida

A Category 4 Landfall in the Keys and a Storm Felt Across the State

At 9:10 a.m. on September 10, 2017, the center of Hurricane Irma crossed Cudjoe Key in the Lower Florida Keys.

Maximum sustained winds were 130 mph. Irma was a Category 4 hurricane.

Florida had spent days preparing. Millions of people had watched Irma approach. Now the hurricane had arrived.

And Cudjoe Key would not be its only Florida landfall.

At approximately 3:35 p.m., Irma struck near Marco Island with sustained winds of about 115 mph, making its second Florida landfall as a Category 3 hurricane.

An Extraordinary Atlantic Hurricane

Irma had already made history before reaching Florida. The storm developed near the Cape Verde Islands and intensified while crossing the Atlantic.

At its peak, Irma produced sustained winds of 185 mph. It maintained extraordinary intensity for more than a day, becoming one of the strongest Atlantic hurricanes observed during the modern satellite era.

Irma devastated portions of the Caribbean before moving along Cuba and turning toward Florida.

Florida Prepares

Unlike Floridians facing hurricanes in 1919—or even 1960—residents in 2017 could watch Irma develop thousands of miles away.

Satellites monitored it. Aircraft penetrated it. Computer models projected possible tracks. Smartphones delivered warnings. Television carried continuous coverage. Government agencies issued evacuation orders.

Yet modern technology could not remove one enormous problem: Florida is a peninsula.

As forecasts shifted, communities on both coasts had reason to prepare. That uncertainty contributed to one of the largest evacuation movements in American history.

Cudjoe Key — 9:10 A.M.

The National Hurricane Center's update was precise. At 9:10 a.m. EDT, Irma made landfall at Cudjoe Key.

The hurricane carried maximum sustained winds of 130 mph. A gust of 106 mph was reported at the National Key Deer Refuge on nearby Big Pine Key.

The Middle and Lower Keys suffered catastrophic damage. Homes were destroyed. Boats were deposited where boats did not belong. Roads were blocked. Utilities failed. Storm surge crossed vulnerable islands.

Communities that had survived hurricanes for generations suddenly faced another enormous rebuilding effort.

Marco Island — 3:35 P.M.

Irma then moved north through the Florida Straits and Gulf waters. At approximately 3:35 p.m., the eye crossed Marco Island. Maximum sustained winds were approximately 115 mph.

A gust reaching 142 mph was measured at Naples Municipal Airport during the eyewall passage.

Southwest Florida experienced severe wind and storm-surge damage. But Irma's immense circulation meant that the consequences extended far beyond the immediate path of the eye.

A Storm Almost as Wide as Florida

One of Irma's defining characteristics was its size. Its enormous wind field allowed Irma to affect communities across much of Florida.

Trees and power lines fell. Millions lost electricity. Roads were blocked. Coastal communities flooded. The effects extended into North Florida, Georgia and Alabama.

Florida's Modern Hurricane Test

Irma demonstrated both the power and limitations of modern hurricane preparedness.

Meteorologists could see the hurricane. Emergency managers could communicate warnings to millions of people. Residents could follow radar almost minute by minute.

Yet evacuating enormous coastal populations remained extraordinarily difficult. Fuel supplies tightened. Highways became congested. Shelters filled.

The experience became an important test of emergency planning throughout Florida.

The Keys Rebuild Again

For the Florida Keys, Irma became another chapter in a very long hurricane history.

The same island chain had endured the 1919 hurricane. It had endured the catastrophic Labor Day Hurricane of 1935. Donna struck in 1960. Georges arrived in 1998. Then came Irma.

Each storm encountered a different Florida. The Keys of 2017 had stronger building codes, sophisticated forecasting, modern communications and organized emergency management.

But geography had not changed. Low islands remained surrounded by warm water. There was still essentially one highway connecting much of the island chain to the mainland.

September 10, 2017

Irma's Florida landfalls occurred on an interesting meteorological date. September 10 is traditionally near the climatological peak of the Atlantic hurricane season.

And on September 10, 2017, one of the most powerful Atlantic hurricanes ever observed arrived in Florida.

It struck Cudjoe Key in the morning. It struck Marco Island in the afternoon. Then its enormous circulation carried damaging winds and rain northward across the peninsula.

Modern Florida had extraordinary technology that earlier generations could scarcely have imagined.

But Irma delivered an old Florida lesson: we can forecast hurricanes far better than our ancestors could. We still cannot stop them.

Sources for Additional Reading

• National Hurricane Center — Hurricane Irma Tropical Cyclone Update, September 10, 2017 — Official Cudjoe Key landfall report.
• National Weather Service — Hurricane Irma 2017 — Florida impacts and storm history.

NOAA, National Hurricane Center and National Weather Service satellite and storm imagery are U.S. government material; FLH links readers directly to the originating agency record.