September 11th, 2017

Hurricane Irma

Posted at 2:41 PM ET

hurricane-irma-smHurricane Irma affected areas of the Caribbean and northern Cuba as a Category 5 hurricane on the Saffir-Simpson Scale, while also passing near Puerto Rico and the Dominican Republic. Impacts in areas of the northern Leeward Islands and northern Cuba have been especially severe. While affecting northern Cuba, Irma weakened to a Category 3 hurricane before turning north towards the Florida Keys.

Irma then crossed the Florida Keys as a Category 4 hurricane, before final landfall on the southwest Florida coast as a Category 3, according to advisories of the National Hurricane Center (NHC). Irma is the first major hurricane to make Florida landfall since Hurricane Wilma (2005). Since Irma made landfall, it has weakened rapidly and is now located in South Georgia as a tropical storm.


Hurricane Irma track and estimated winds. Source: Guy Carpenter, NOAA/NHC

Hazard data illustrated in the CAT-i map was taken from GC AdvantagePoint®, Guy Carpenter’s web-based risk management platform. GC AdvantagePoint users can view impacted areas on any map as well as see how their portfolios were affected. Please contact your broker or cat modeling analyst for further information.

Irma is a large storm, and has rendered impacts of storm surge, inland flood due to heavy rain and variable wind impacts over an especially large area. Impacts in the Florida Keys area are especially severe, and an ongoing threat due to storm surge remains active for areas including Saint Augustine and Jacksonville, according to media reports. It will take time to fully assess the full scope and severity of this ongoing event, and our first thoughts and concerns are with those directly affected.

Meteorological Discussion

Irma is the first major hurricane to affect Florida since Hurricane Wilma (2005).

Hurricane Irma crossed the northern Leeward Islands as a strong Category 5 hurricane on the Saffir-Simpson Scale and passed just north of Puerto Rico. Irma then affected northern Cuba as a Category 5 hurricane and then weakened to a Category 3 hurricane due to land interaction. Irma then turned north towards the Florida Keys through a break in the subtropical ridge. While approaching the Florida Keys, Irma was able to gain intensity over warm waters, and re-intensified to a Category 4 hurricane with maximum sustained winds of 130 mph.

According to advisories of the NHC, Irma made landfall near Cudjoe Key in the Lower Florida Keys at 9:10 a.m. EDT (13:10 UTC) Sunday, September 10. Maximum sustained winds at landfall were 130 mph, a Category 4 hurricane on the Saffir-Simpson Scale. Minimum central pressure at the time of landfall was 929 millibars (mb). Following landfall in the Florida Keys, Irma weakened slightly on approach to southwest Florida. Irma then made landfall on Marco Island in southwest Florida, about 15 miles south-southwest of Naples at 3:35 p.m. EDT (19:35 UTC), with maximum sustained winds of 115 mph. Irma made final landfall as a Category 3 hurricane on the Saffir-Simpson Scale, with a minimum central pressure of 940 mb.

While then moving through the western Florida Peninsula, Irma weakened steadily due to increased wind shear and land interaction. Irma weakened to a Category 1 hurricane at 2 a.m. EDT (6 a.m. UTC) this morning, and then was downgraded to a tropical storm at 8 a.m. EDT (12 p.m. UTC) this morning, according to National Hurricane Center (NHC) advisories.

Irma is still a very large and dangerous tropical storm, with an ongoing threat of storm surge, damaging winds and flash-flooding due to heavy rainfall. Irma is now located about 10 miles east of Albany, Georgia, according to the 5 p.m. EDT (21 UTC) NHC advisory. Maximum sustained winds are now 50 mph, with a central pressure of 985 mb. Hazards extend well away from the center of the storm, including an ongoing threat of storm surge in the Jacksonville and Saint Augustine areas. Irma should continue to weaken while moving toward the Central Mississippi Valley, where it should eventually dissipate.



In the Caribbean, at least 26 fatalities have been reported as a result of Irma. Nine were in various French territories, one in Barbuda, one in Anguilla, four in St. Maarten, four in the British Virgin Islands, four in the US Virgin Islands, and three in Puerto Rico. So far there have been reports of at least 10 fatalities in Cuba. The Prime Minister of Barbuda, Gaston Browne, described the result of Irma as “total devastation.”

In St. Maarten, a team of 59 urban search and rescue experts is being deployed to survey the damage from Irma. Based on initial media reports, 70 percent of homes were badly damaged. The Dutch government is also sending extra troops to St. Maarten to maintain order following widespread looting and robberies.

Irma caused roughly USD 1.44 billion (1.2 billion Euros) of insured damage in the French portion of St. Martin and in St. Barts, according to French state-owned insurer CCR. The estimate includes damages to homes, vehicles and businesses, which are covered by the natural disaster compensation scheme.

Irma made landfall in Cuba overnight on Friday as a Category 5 storm causing flooding in low-lying areas of the capital Havana. Powerful waves and storm surge from Irma topped Havana’s Malecon seawall and left thousands of homes, businesses and hotels flooded on Sunday. Hurricane-force winds of up to 125 mph also damaged buildings, uprooted trees and forced more than one million people to evacuate along the coast.

The U.S. and British Virgin Islands were also impacted by Irma. St. Thomas, the most populated of the U.S. Virgin Islands, showed extensive damage. St. Thomas, St. John and Water Island have been without any electrical service for more than five days.

Puerto Rico avoided a direct hit from Irma but suffered strong winds and torrential rains. Hundreds of thousands of people lost power due to the storm.

Strong winds and heavy rain also impacted the Dominican Republic, Haiti and the low-lying Turks and Caicos Islands Thursday and Friday. The Governor of Turks and Caicos, John Freeman, advised the capital island of Grand Turk suffered “quite a bit of damage,” including to part of a hospital’s roof, according to media reports.


At least three fatalities were reported due to Irma in Florida. Two deaths occurred in Hardee County and one death was reported in Orange County. It is too early to determine the full scope and severity of impacts for this historic event and full damage assessments could take several days to weeks to complete.

The Governor of Florida activated all 7,000 members of the Florida National Guard and 10,000 guardsmen from other states were also being deployed, according to media reports. The President approved a disaster declaration for Florida to allow for the deployment of federal aid.

An evacuation order was issued to nearly seven million people in Southeast Florida. More than 200,000 people are waiting in shelters across Florida, according to media reports.

Nearly 4.5 million homes and businesses across Florida lost power and it will take weeks to restore electricity to all areas, according to utility officials. The storm collapsed at least three construction cranes, two over downtown Miami and one in Fort Lauderdale, causing damage to surrounding buildings. No injuries were reported from the crane collapses but residents were warned that approximately 25 cranes in Miami were not dismantled before the storm arrived and posed as an ongoing threat, according to media reports.

In the Florida Keys, especially severe damage has been reported by media. The area is without power and damage to the Florida Keys Aqueduct Authority’s transmission lines, which impacts the flow of fresh water to the island chain, was reported. In the low-lying Keys, storm surge was recorded excess of 10 feet (three meters) and appliances and furniture were seen floating in the ocean water. Cammy Clark, a Monroe County spokeswoman, advised the ocean waters were filled with navigation hazards including sunken boats. The Monroe County Sheriff, Rick Ramsay, declared an indefinite dusk-to-dawn curfew.

In Central Florida, Orange County Mayor, Teresa Jacobs stated that there is widespread damage and significant power loss throughout the area, according to media reports. Approximately 300,000 residents in Orlando are without power. More than 120 homes were being evacuated early Monday in Orange County due to flooding hazards. A 60-foot sinkhole opened up under an apartment building a few miles outside of Orange County and 30 people had to be evacuated. No injuries have been reported from the incident.

In Miami, the state’s largest electric utility, Florida Power & Light, reported nearly 3.3 million homes and businesses are without power in Miami-Dade County alone. Police in Miami are investigating reports of people looting stores, according to media reports.  A tornado was reported in Palm Bay as a result of Irma, which destroyed six mobile homes. Baptist Health South Florida is sheltering more than 6,000 people in its five Miami-Dade hospitals. The total includes 1,400 patients, roughly 3,000 doctors and nurses and their 3,000 family members.

In Northern Florida, people were being rescued from flooded homes Monday morning due to heavy rain and strong winds. John Ward, the emergency operations manager of Clay County, advised 46 people were retrieved from flooded homes and an undetermined number are still stranded in the area. Ward says between 400 and 500 homes received severe flood damage but there have been no serious injuries or deaths. More than 26 river gauges in northern Florida are in major flood stage, according to media reports. Recent media reports indicate an ongoing, significant threat of flooding in the Saint Augustine and Jacksonville areas as a result of storm surge.

CoreLogic estimates 8.5 million properties in Florida were at significant risk of wind damage from Irma, with approximately 3.5 million properties at risk for storm surge.

Orlando International Airport closed Saturday and will not reopen to passenger traffic until after Irma has passed, a damage assessment has been completed, necessary recovery efforts made, and the airlines are consulted to determine when best to resume operations. Tampa International Airport is also closed as Irma moves up the Florida peninsula. Miami International Airport announced it will be closed Monday and begin only limited flights on Tuesday. The airport sustained more than 100 mph wind gusts and suffered significant water damage, according to media sources. More than 3,800 flights scheduled for Monday were cancelled and more than 9,000 flights were cancelled since Saturday, according to media reports.


Governor Nathan Deal declared a state of emergency for Georgia. Hazard concerns include ongoing strong wind gusts, tornadoes and heavy rainfall which could cause swollen rivers, streams and creeks to overflow.

Georgia Power reported more than 125,000 customers were without power across Georgia’s six coastal counties.

Andrew Gobeil, a spokesman from Hartsfield-Jackson Atlanta International Airport, advised that the airport will still be operational Monday and will monitor storm conditions. An airport official reported approximately 800 cancellations due to the threat of Irma.  Atlanta’s public transit system has suspended all bus and rail service ahead of the weather conditions caused by Irma, according to media reports.

South Carolina

A flash flood warning is in effect along the southern coast of South Carolina, where more than 40,000 were ordered to evacuate barrier islands, according to media reports. South Carolina Electric & Gas reported more than 13,000 customers without service Monday morning.

AIR Worldwide estimates insured losses from Irma for the United States of USD 20 billion to USD 40 billion. These estimates are based on the September 10, 5 p.m. EDT (9PM UTC) NHC forecast advisory for Irma. According to AIR, exposure value in the coastal counties along the Gulf Coast up to Tampa is estimated at USD 1 trillion. These loss estimates include impacts from wind and storm surge and time element coverage but do not include losses rendered to the National Flood Insurance Program, losses to uninsured properties, losses to inland marine, marine cargo and hull and pleasure boats, and losses to infrastructure.

RMS estimates that there is a 10 percent chance of insured wind losses from Irma exceeding USD 60 billion. The estimate does not include contributions from storm surge or post-event loss amplification.

Sources: Reuters, Associated Press, National Hurricane Center, National Weather Service, The Weather Channel, AIR Worldwide, Risk Management Solutions, CoreLogic, The Financial Times

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Guy Carpenter publishes CAT-i reports for major natural catastrophes worldwide. These reports cover catastrophes including worldwide tropical cyclones, earthquakes, major UK and European floods and any other natural event that is likely to incur a significant loss to the (re)insurance industry. Please email if you wish to be added to the free email distribution list.

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