Dean was 3rd-most intense hurricane
By JOHN PAIN, Associated Press Writer
MIAMI - Hurricane Dean was the third-most intense Atlantic hurricane to make landfall since record keeping began in the 1850s, based on its central atmospheric pressure, forecasters said.
The pressure in a hurricane's eye is often used to compare storms throughout history because in the past, wind gauges were often damaged or destroyed by powerful hurricanes. Now, technology exists to more accurately measure winds, said Jamie Rhome, a hurricane specialist with the National Hurricane Center.
"And the damage is caused by the wind, so that's what most people look at," he said.
But pressure also measures strength: the lower the pressure, the greater a hurricane's power to suck in air. A hurricane's winds are blown because higher-pressure air rushes toward the lower-pressure eye to equalize the difference.
Typically, the lower the pressure, the faster the air speeds in. But because of other variables in each storm, a certain pressure does not always correspond to a specific wind speed.
Dean was a top-scale Category 5 storm at landfall Tuesday on Mexico's Yucatan Peninsula. Its maximum sustained winds were 165 mph and gusts reached 200 mph. Just before landfall, a Global Positioning System device dropped from a hurricane hunter aircraft found it had a central pressure of 906 millibars, forecasters said.
The only other storms that hit land with a lower pressure were the 1935 Labor Day hurricane that hit the Florida Keys and Hurricane Gilbert, which hit Cancun, Mexico, in 1988, forecasters said.