Dean was third-most powerful hurricane at landfall

Meteorologists will be sorting through data from Hurricane Dean for months analyzing this incredibly powerful storm, but a few facts are already clear.

Hurricane Dean is the ninth-most powerful hurricane on record for the Atlantic Basin, which includes the Caribbean Sea and the Gulf of Mexico. Dean’s lowest recorded barometric pressure was 906 millibars, which was recorded on August 21 at around 4 a.m. Eastern Daylight Time. At that time, its sustained winds were clocked at 165 miles and hour, with gusts to 201 miles an hour.

A hurricane’s intensity is measured by its lowest barometric pressure reading and its peak sustained winds. A sustained wind is one that is measured continuously for at least one minute.

A very low barometric pressure reading is an indicator of very powerful winds.

The Saffir-Simpson Scale, which was devised by engineer Herbert Saffir and meteorologist Robert Simpson in the late 1960s, classifies hurricanes according to their destructive potential. Hurricane Dean became a Category 5 storm on the Saffir-Simpson Scale. Category 5 storms are capable of causing catastrophic damage if they make landfall. These are the storms that level nearly everything in their path. The energy a Category 5 storm releases can only be measured by comparing it to the detonation of multiple atomic bombs.

Hurricane Wilma, which roared across the Caribbean Sea in October 2005, is the most powerful storm in the Atlantic. As Wilma approached a landfall at the tip of Mexico’s Yucatan Peninsula, its barometric pressure bottomed out at 882 millibars. At that point, its peak sustained winds were 170 miles an hour.

But luckily, Wilma weakened before it reached the Yucatan and made a right-angle turn toward the Florida Keys.

Although there are eight storms that reached greater intensity than Dean, only two other storms were stronger than Dean when they made landfall. The Labor Day hurricane of 1935 – which struck the Florida Keys on September 2, 1935 – is still the most powerful hurricane to strike the United States. The official low for this storm was 892 millibars when it came ashore at Long Key.

Hurricane Gilbert, which came ashore in 1988 at very near the same spot as Wilma, had a barometric pressure of 888 millibars.