By CBC Docs  

In just one devastating month, Houston, Florida, and the Caribbean were changed forever. Three monster hurricanes swept in from the Atlantic during the summer of 2017, one after another, shattering storm records and killing hundreds of people. The Passionate Eye documentary Rise of the Superstorms asks the question: “Is the historic devastation caused during the 2017 Atlantic hurricane season the new normal?”

Understanding these powerful storm systems is more critical than ever. Here are 10 facts and figures about hurricanes.

hurricane destruction

An aerial view of the Florida Keys displays the damage sustained from Hurricane Irma Sept. 12, 2017.

Hurricanes are the most powerful storms on earth. They are rotating tropical cyclones with wind speeds of at least 119 kilometres per hour, a low-pressure centre and thunderstorms producing heavy rains.

What is the difference between cyclones, hurricanes and typhoons? Their origin point. Tropical cyclones that develop in the Atlantic Ocean and eastern Pacific Ocean are called hurricanes. If they develop over the western Pacific, they are called typhoons, and they are known as cyclones when they develop in the Indian Ocean.

hurricane destruction

Rockport, TX home destroyed by Hurricane Maria upon landfall.

The 2017 hurricane season was unprecedented. Three devastating hurricanes swept in from the Atlantic one after another. In late August, Hurricane Harvey brought catastrophic rain and flooding to the Houston area with some locations receiving 1,539 mm of precipitation. The sheer volume of rainwater fallen is enough to fill the Houston Astrodome 85,000 times. Less than two weeks later, Hurricane Irma lashed the Caribbean — decimating the island of Barbuda — and hit the Florida Keys. Irma was unusual because it maintained its top wind speeds of 290 kilometres per hour for 18 straight hours. Hurricane Maria was one of the most rapidly intensifying hurricanes on record, increasing from a tropical depression to a Category 5 hurricane in just 54 hours, ravaging Puerto Rico in September 2017, and leaving millions of people without power.

From tropical storm to hurricane: Hurricanes begin as tropical disturbances in warm ocean waters. A tropical depression forms when a low-pressure area is accompanied by thunderstorms. Once this tropical storm reaches sustained wind speeds of greater than 63 kilometres per hour, it is given a name.  If storm’s sustained wind speeds continue to grow, reaching 119 kilometres per hour, it becomes a hurricane and earns a category rating of 1 to 5 on the Saffir-Simpson scale.

The spin of the storm. Storms that form north of the equator spin counterclockwise. Storms south of the equator spin clockwise.

The costliest storm. Hurricane Harvey is tied with Hurricane Katrina in 2005 as the costliest hurricane on record, causing $125 billion (USD) in damage.

The deadliest storm. The deadliest recorded storm was the Bhola cyclone that struck East Pakistan, present-day Bangladesh, on November 12, 1970. Up to 500,000 people lost their lives. The deadliest Atlantic hurricane on record was The Great Hurricane of 1780. It struck the Lesser Antilles in October killing 20,000 - 22,000 people.

The biggest storm. Typhoon Tip holds the record as the most intense tropical cyclone, reaching peak winds of 305 kilometres per hour on October 12, 1979. At its peak strength, it was also the largest tropical cyclone on record, with a wind diameter of 2,220 kilometres roughly the distance from New York City to Dallas, Texas.

Hurricane hunters measure hurricane intensity. To gather accurate measurements of pressure, wind speed, temperature and humidity, aircrews known as Hurricane Hunters fly directly into the storm, penetrating the hurricane’s eyewall. These measurements help to hone forecasts, which can dramatically affect the reaction to an upcoming storm. In 1943, Colonel Joseph Duckworth became the first person to fly into the eye of a hurricane when he flew a single-engine plane into a Category 1 storm near Galveston, Texas.

hurricane flooding

Staff Sgt. Joseph Baker, LUH72 Lakota crew chief, 36th Combat Aviation Brigade, Texas Army National Guard, scours miles of Hurricane Harvey flooded areas for survivors north of Beaumont, Texas, August 31, 2017.

Is there a connection between climate change and worsening hurricanes? Since reliable hurricane data only goes back to 1851, it’s difficult to differentiate climate change from other weather patterns. But, for every one-degree Celsius the air warms, it can hold 7% more water, leading to more intense rainfall. And rising sea levels mean more dangerous storm surges, which contribute to a hurricane’s destruction.

Watch Rise of the Superstorms.