August 19, 1955…and 2011

In 1955, Hurricane Diane swept up the Atlantic coast of the United States, making landfall at North Carolina on August 17th and taking a couple of days to slowly work its way up the coast. 66 years ago today, it was working its way across New England. By that time it had turned into a major rainmaker, dropping nearly 20” of rain over much of Connecticut, Rhode Island, and Massachusetts. Flooding throughout New England was massive and extensive.

The storm was a killer. Nearly 200 people died from the winds and floods. Coming on top of the casualties and damage from Hurricane Connie, which had hit the Carolina coast just five days earlier, the storm produced damage estimated at $800M, in the currency of that year, which with inflation translates to over $3B today.  This loss made it the costliest hurricane in US history up until that time. Diane held this record until Hurricane Betsy in 1965.

Making allowances for inflation, Hurricane Diane still remains one of the top ten costliest US hurricanes over the period 1900-2004, according to the National Weather Service.

That adjustment for inflation? Notice that’s all it is. The adjustment makes no additional allowance for any population increase that has occurred in the area since 1955, or for changes in wealth per capita. These trends indicate a greater property exposure to such a storm in 2011. Pielke et al., writing in Natural Hazards Review in 2008, provide an interesting discussion and analysis of these factors as they apply to US storms over the period 1900-2005. [They also review previous analyses.] They conclude that if Hurricane Diane were to recur today, losses would be in the $17B range (let’s call it $15-20B). [For a link to that work, click here.]

Sobering.

New England hurricanes are rare but not unknown. Perhaps the most famous storm of record was the Great Hurricane of 1938 (that label tells you something right there). It was the first major hurricane to hit New England since 1869 – a gap of nearly 70 years. It killed some 700 people and produced perhaps $300M in damages.

Adjusting for inflation? Damages just short of $5B today. But according to the more thorough Pielke et al. analysis? $40B. Whew!

Juxtaposing these two storms shows as many contrasts as similarities. Diane was noteworthy not because it was particularly strong, but because it was painfully slow. It made landfall in the Carolinas, and moseyed up the U.S. coastline. It produced so much damage because it was a big rainmaker and lingered over every state in its path.

By contrast, the 1938 storm was intense indeed. It also moved rapidly, perhaps as fast as 50 miles per hour. At these speeds, the cooling from the cold surface waters didn’t have much time to choke off the storm’s energy supply. It made landfall directly onto New England, and it killed through high winds and storm surge, intensified by prevailing high tides at the time of landfall. The storm surge was particularly dramatic in Providence, where channeling of the surge by Narragansett Bay led to 13 feet of inundation. Want to read more? There are lots of books on this one; I can recommend Sudden Sea: the great Hurricane of 1938, by R. A. Scotti.

One similarity? The populations affected weren’t particularly well prepared. In the time between 1869 and 1938, European immigrants swelled the population of New England; hurricanes were not a part of their culture. Ask any New Englander today whether hurricanes can affect the region, and he or she’ll likely answer “yes,” but that’s head knowledge as opposed to the kind of familiarity Gulf- and Florida coastal residents have with the threat, or the Oklahoman’s awareness of tornadoes, or the Californian’s understanding of earthquakes – an understanding that will lead to effective action in the event. When it comes to winter storms, New Englanders have that savvy. When it comes to hurricanes, they’ll likely be caught flatfooted.

Why bring this up? Weather warnings are far better today. They’re more accurate, and provide longer lead times. And August 19th, 2011 finds no immediate threat to the New England coast. The National Weather Service website is highlighting Tropical Depression 8, which is headed for southern Mexico and the northern bits of Central America.

But the fact remains that the entire Atlantic coast of the United States, not just those southern states that we all tend to view as “hurricane-prone,” is vulnerable. And “vulnerable” means not if, but when

Do you live in New England? Are you wondering what you can do? Well, chances are good that your house can withstand fairly high winds. You and your neighbors have seen those before – in those pesky winter storms, and from the trademark nor’easter. But the more salient issues are storm surge and flooding. Live near the coast? Google “New England Storm surge maps” and start digging a little deeper. Live near a lovely creek or river, where you get to watch the migratory waterfowl and enjoy all those other recreational values? Get your head around what that river will do in response to 20” of rain upstream. Find your house on sites such as FloodSmart.gov and the links therein.

You can minimize your risk by living away from the coasts and out of the floodplain. But if you must live in such areas, because of the many other benefits they provide, then shoulder individual responsibility for your family’s safety and for your financial well-being. Buy the flood insurance. Develop and exercise an evacuation plan.

Those folks who lost their lives 66 years ago today? They’d want you to take these steps.

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