New damage estimates released last month by NOAA now place the damage from 2011′s Hurricane Irene at $15.8 billion, making the storm the 6th costliest hurricane and 10th costliest weather-related disaster in U.S. history. Irene hit North Carolina on August 27, 2011, as a Category 1 hurricane with 85 mph winds, and made landfalls the next day in New Jersey and New York City as a tropical storm. Most of the damage from Irene occurred because of the tremendous fresh water flooding the storm’s rains brought to much of New England. Irene is now rated as the most expensive Category 1 hurricane to hit the U.S. The previous record was held by Hurricane Agnes of 1972, whose floods did $11.8 billion in damage in the Northeast. NOAA also announced that the name Irene had been retired from the list of active hurricane names. Irene was the only named retired in 2011, and was the 76th name to be retired since 1954. The name Irene was replaced with Irma, which is next scheduled be used in 2017.

Figure 1. True-color MODIS image of Hurricane Irene over North Carolina taken at 11:35 am EDT August 27, 2011. At the time, Irene was a Category 1 hurricane with 85 mph winds. Image credit: NASA.

At last month’s 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society, Paul Ruscher of Florida State University explained how Irene’s storm surge came within 8 inches of flooding New York City’s subway system, which would have caused devastating damage. At the current global rate of sea level rise of 3.1 mm/year, a repeat of Irene 65 years from now would be capable of flooding the subway system, if no action is taken. To read more about New York City’s vulnerability, see Andrew Freedman’s analysis at Climate Central, Climate Change Could Cripple New York’s Transportation, or my November 2011 blog post, Hurricane Irene: New York City dodges a potential storm surge mega-disaster.

Jeff Masters