Source: USA TODAY research by Chad Palmer

Bomb cyclones ravage northwestern Atlantic

By Jack Williams, USATODAY.com

Over the years, sudden, intense storms have sunk many ships in the northwestern Atlantic Ocean.

These storms are often mistaken for hurricanes because they an spawn 74 mph and faster, hurricane force winds.

In the 1940s some meteorologists began informally calling some of these storms "bombs" because they develop "with a ferocity we rarely, if ever, see over land," said Fred Sanders, a retired MIT professor, who brought the term into common usage by describing them in a 1980 article in the Monthly Weather Review.

Similar storms also form in the western Pacific off the Asian Coast, and occasionally in the eastern Atlantic and Pacific oceans.

Today, a bomb cyclone is an extratropical area of low pressure in which the central barometric pressure drops at least 24 millibars in 24 hours. Some storms have intensified as rapidly as 60 millibars in a 24 hour period. A few bomb cyclones even develop "eyes", similar to the center of a hurricane.

Some bomb cyclones are hybrid storms, which share some other characteristics with hurricanes. (Related explanation: Subtropical (hybrid) storms)

Even though bomb cyclones sometimes share characteristics with hurricanes, it is important to note that they are not hurricanes the two kinds of storms are different in important ways

• Bomb cyclones have cold air and fronts. Cold air rapidly weakens hurricanes while it is an essential ingredient for bomb cyclones.
• Bomb cyclones form under strong upper-level winds. Strong high altitude winds associated with intense upper-level disturbances would destroy a hurricane, but are a necessity for bomb cyclone development, also known as bombagenesis.
• Bomb cyclones form during winter. Hurricanes form from late spring to early fall while bomb cyclones form from late fall to early spring.
• Bomb cyclones form at higher latitudes. Hurricanes form in tropical waters while bomb cyclones form over the northwestern Atlantic, northwestern Pacific and sometimes the Mediterranean Sea.

Many of the famous blizzards and northeasters that battered the East Coast and sank ships in the northwestern Atlantic Ocean throughout history were bomb cyclones.