Satellite imagery of Category 5 Hurricane Dorian on Sept. 1, 2019. It's now considered the "strongest hurricane in modern record." [National Hurricane Center]

A Review of the Atlantic Hurricane Season of 2019

An ultraintense hurricane—Dorian—and multiple destructive slow-moving storms: Are they harbingers of the future?

With the demise of Tropical Storm Sebastien on November 24, we’ve likely seen the end of the 2019 Atlantic hurricane season, with a final tally of 18 named storms, 6 hurricanes, 3 intense hurricanes, and an ACE index of 129.8. The 1981 – 2010 averages for these quantities were 12.1 named storms, 6.4 hurricanes, 2.7 intense hurricanes, and an ACE index of 106, according to data from Colorado State University, so 2019 was near or above average in all metrics.

The season had two ominous harbingers of a warming climate: an ultra-intense hurricane--worthy of a category 6 rating if such a thing existed--and multiple damaging storms that moved very slowly at landfall. The ultra-intense hurricane was Hurricane Dorian, whose 185 mph winds devastated The Bahamas in early September when the mighty category 5 storm stalled over the islands. Dorian and Lorenzo (in far eastern Atlantic) were both category 5 storms, making 2019 the fourth consecutive year in which a category 5 storm developed in the Atlantic basin--a new record.

The damaging slow-moving storms of 2019 were Hurricane Barry (Louisiana, $600 million in damage), Hurricane Dorian (The Bahamas, Southeast U.S. and Canada, at least $4.6 billion in damage), Tropical Storm Imelda (Texas and Louisiana, $2 billion in damage), and Tropical Storm Fernand (northeast Mexico, $250 million in damage). All four storms moved at 8 mph or slower for two or more days near the time of landfall; the average forward speed of a tropical cyclone is about 11 mph.

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