Image: NASA Earth Observatory

Myth: Sandy hit the U.S. Northeast as a hurricane
 

Perhaps the greatest myth of all is that Sandy was a hurricane for its entire journey up the U.S. eastern seaboard. There's no doubt that the storm packed a punch, but the National Hurricane Center downgraded it from hurricane to "tropical storm" on Monday, October 29.

Why the switch? The center uses a sliding scale called Saffir–Simpson to categorize hurricanes. The scale is based solely on wind speed. So when Sandy's wind velocity decreased, the storm also lost its hurricane status.

The lesser label presents a communications problem for scientists who study storm surges and for public officials who have to make evacuation decisions for entire populations because of flooding. The demotion from hurricane to tropical storm does not make the event any less deadly, says Noah Diffenbaugh, a climate scientist at Stanford University.

"We have plenty of examples of lower category storms that cause a greater level of damage and higher category storms that cause a lower level of damage," he says.

The mismatch between a storm's status and the damage it can inflict is a consequence of a gradual increase in the size and intensity of storms overall, says Rice's Bedient. As storms grow larger and more intense, their impacts might have outgrown the Saffir–Simpson scale. "We're getting these really huge storms," he adds. "They can have enormous storm surge effects compared to what we saw back in the '50s and '60s."

The meteorological community has proposed other ways of measuring hurricanes, but some researchers stand in staunch support of Saffir–Simpson. Scientific American previously covered the debate. —Mollie Bloudoff-Indelicato

8 Comments

1. 1. hanmeng 04:11 PM 11/9/12

   7. Readers love to click multiple times to read a single article.

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2. 2. Georgevv 12:31 AM 11/10/12

   re: effect of "spring" tides on storm surges. The author states the effect probably would be only a few centimeters. I have observed several spring tides along the central NJ shore and the effect is more like 1 - 2 feet higher than on a week before or after a spring tide. The low tides during spring tides times are extreme also with large areas of wet sand being exposed that is normally covered other times. Another effect on storm surges that I have never seen mentioned is low barometric pressure. Think of "sucking" water up a straw. A drop in pressure of 10% would cause a rise of nearly a meter even if there were no other factors involved!

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3. 3. northernguy in reply to Georgevv 12:34 AM 11/11/12

   
   2. Georgevv...
   
   Thank you for your comment. I thought maybe things are different on the east coast.
   
   Here on the west coast spring tides have significantly greater swings in water movement. The difference can easily be seen by anyone who pays attention. A difference of a couple of inches wouldn't even be noticeable.

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4. 4. Danm1701 in reply to hanmeng 05:40 PM 11/11/12

   I do. I wish I could click every other word. It's so informative and entertaining.

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5. 5. m allworth 11:03 AM 11/12/12

   Is Cumbre Veijo still being monitered?
   
   Let us hope that the volcano holds secure.
   
   Best wishes,
   
   
   Marg.

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6. 6. Christine Gorman 12:02 PM 11/16/12

   hanmeng: Just hit the print button and you'll see the whole article. No extra clicking necessary.

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7. 7. N49th 09:56 PM 11/17/12

   Children were lost, White, black, red and brown.
   Can't bring them back.
   All I know is they are playing for Jesus's soccer team.

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8. 8. N49th 10:02 PM 11/17/12

   i do know where the United States Navy is off shore.
   Might want to shut up.

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