NewsMay 10, 2012

Hurricane Irene Ranked Most Costly Category 1 Storm

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Andrew Freedman

By Andrew Freedman

Hurricane Irene, which first made landfall in North Carolina on August 27, and went on to cause devastating flooding in several Northeastern states, is now ranked as the costliest Category One storm to strike the U.S. According to the National Oceanic and Atmospheric Administration (NOAA), Irene caused $15.8 billion in damage, much of it due to inland flooding.

The track and strength of Hurricane Irene. Click on the image for a larger version. Credit: National Hurricane Center.

This ranking is a testament to how much expensive real estate the storm struck, as it marched up the eastern seaboard, passed directly over New York City, and swept through northern New England. Fortunately, the storm weakened prior to hitting New York, but fears of coastal flooding from the storm surge caused the mayor's office to issue an unprecedented evacuation of low-lying areas of the city, and shut down the entire transit system for the first time.

As we reported last month, Irene posed a major threat to the city's subway system, which is prone to flooding from heavy rainfall, let alone a significant storm surge. Despite the storm's weakened state, the Atlantic Ocean still came within a few inches of flooding subway tunnels in lower Manhattan.

Irene eclipsed 1972's Hurricane Agnes to take the crown for the most expensive Category One storm. Both Agnes and Irene caused major inland flooding, but Irene was not nearly as deadly as Agnes, killing 48 people compared to Agnes' 122. This is probably related to the advancements in weather forecasting that have been made since the 1970s.

Of Irene's 48 deaths, 40 of them occurred in the U.S., and the biggest cause of death was inland flooding, which is also the biggest weather-related killer in the U.S.. Flooding was especially damaging in Vermont and New York, where some communities are still working to recover after the storm turned small streams into raging rivers, taking out covered bridges, homes, and other infrastructure.

The $15.8 billion price tag also makes Irene the sixth-costliest hurricane on record in the U.S., just behind Hurricane Charley, a compact Category Four storm that roared into Southwest Florida in 2004, causing $15.82 billion in damage.

Hurricane experts, along with the insurance industry and others, have been warning for years that the buildup of homes and businesses in coastal areas, many of them located in areas frequented by powerful hurricanes in the past, will continue to drive storm damage upwards, regardless of the effects that global warming may have on hurricanes.

At the same time as coastal areas have been built up, global warming-related sea level rise has begun to accelerate, and this promises to make the storm surge from any land-falling storm, even a lowly Category One like Irene, more damaging.