Introduction: Killer Hurricanes (01:58)

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More than 200 years ago, a disaster tears through the Caribbean. The Great Hurricane of 1780 is the deadliest hurricane in the region. Experts will attempt to trace its impact with today's tools, and the possibility of future extreme hurricanes.

Irma and Maria (03:09)

Two record-breaking hurricanes strike the Caribbean in September 2017. Irma leaves a trail of destruction across the islands of Barbuda, St. Martin, and St. John. Maria blasts Puerto Rico, leaving millions stranded without clean water, food, gas, or phones. There is growing evidence that hurricanes of this magnitude were once more common.

Great Hurricane Documented (04:05)

The hurricane of 1780 strikes the Caribbean, killing an estimated 22,000 people and destroying every building on the island of Barbados. Multiple storms devastated the region in quick succession.

Hurricane Irma Formation (02:23)

Irma begins as a storm off the west coast of Africa on Aug. 27, 2017 and quickly gathers strength as it crosses the Atlantic Ocean. It is a Category 5 storm by the time it reaches Barbuda on Sept. 6.

Great Hurricane of 1780 (05:52)

Historians determine the hurricane's strength using ship records kept by competing naval powers during the Revolutionary War. Mike Chenoweth plots the hurricane's location in six-hour intervals and identifies two features that make the storm so destructive

Monster Hurricane Formation (01:43)

Scientists agree there are three key ingredients for the perfect storm: a layer of warm ocean water reaching down at least 200 feet, crosswinds near the top of the hurricane that are not too strong, and moisture throughout the atmosphere. Wind speeds within the eyewall can rapidly increase if all these conditions come together.

Categorizing Hurricanes (02:12)

On a scale of one to five, a major hurricane is a Category 3 storm or above, with wind speeds of 111 miles an hour or greater. Category 5 storms have wind speeds exceeding 156 miles an hour. The deadliest storm ever to hit the United States is a Category 4 storm that struck Galveston, Texas, in 1900.

Storm Surge (04:18)

Chenoweth believes storm surge was responsible for many of the casualties of the Great Hurricane of 1780. The most powerful storms push tsunami-like waves ashore, as when Typhoon Haiyan ravaged the Philippines in 2013. Wayne Neely visits Fort Charles, rebuilt after surge destroyed the original.

Reconstructing the Storm (02:17)

The Great Hurricane of 1708 approaches Barbados from the southeast on Oct. 9; it is more than 300 miles across. Wind and rains lash the island on Oct. 10 before the storm’s eye wall reaches land, pushing a 25-foot storm surge. A hurricane of that intensity occurs only about once every 400 years.

Climate Change and Hurricane Patterns (06:38)

Scientists predict intense hurricanes will become more common thanks to greenhouse gases. Data is lacking to determine hurricane patterns from the distant past. Oceanographer Jeff Donnelly extracts sediment from a sinkhole off the coast of Jamaica that may help fill in the gaps.

Ocean Surface Temperature (06:35)

Donnelly sees a pattern emerge as he plots the dates of major hurricanes going back 1,400 years. He studies coral to establish a correlation between hurricane frequency and ocean surface temperature. Scientists agree that global climate change will contribute to storms of increasing intensity.

Where Will Future Hurricanes Strike? (05:30)

Paleoclimatologist Amy Frappier studies stalagmites to determine hurricane patterns over time. She pinpoints a pattern of hurricanes migrating northward, from the Caribbean to densely populated areas along the Eastern seaboard.

Eastern Seaboard Vulnerability (05:05)

The last major storm to hit the northeast coast is Hurricane Sandy, in October 2012. It is a Category 1 storm, but a 14-foot storm surge floods streets, tunnels and subways. The 1821 Norfolk and Long Island Hurricane, believed to have been a Category 4 storm, is a reminder that the region is vulnerable.

Credits: Killer Hurricanes (00:32)

Credits: Killer Hurricanes