Thursday marks the official end of the 2017 hurricane season after leaving a path of death and destruction in the U.S. and the Caribbean.
The Atlantic Ocean had a total of 17 named storms, the ninth-most on record since 1851, according to the National Oceanic and Atmospheric Administration. Ten of those storms became hurricanes, with six classified as major hurricanes.
Fueled by warmer than normal ocean temperatures and ideal wind conditions, September had more days with major hurricanes spinning and more overall hurricane energy expelled than any month on record, according to Colorado State University hurricane researcher Phil Klotzbach.
Harvey, the first major hurricane to hit the U.S. mainland in a dozen years, set a new U.S. record for rainfall. Irma followed, hammering Florida and Puerto Rico with fierce winds that made it the strongest hurricane ever recorded outside the Caribbean or Gulf of Mexico. Then Maria pounded Puerto Rico, further crippling it.
But more intense storms are what scientists expect to see as the planet's climate changes because warmer ocean water is fuel for hurricanes. And they say it is important to better understand this current intense period to save lives and prevent worse future destruction.
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Georgia Tech climate scientist Kim Cobb said it would be "foolish" for policymakers to ignore the data. "We may not have as much data as we would like, but we have enough to aggressively invest in a variety of defenses for coastal communities," she said in an email. "We face a triple threat of rising seas, stronger winds, and literally off-the-charts rainfall totals."
The Atlantic hurricane season was more intense than normal in 2003, 2004, 2005, 2008, 2010, 2012 and 2016. The 2005 season, which included Katrina, Rita and Wilma, was so active forecasters ran out of names for storms.
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This year's hurricane season also broke another record: it was the costliest.
The combined tab from hurricanes Harvey and Irma is expected to hit $200 billion, according to a preliminary estimate from Moody's Analytics. Hurricane Maria is likely to cause between $45 billion and $95 billion worth of damage in Puerto Rico, Moody's reported. The previous record of $211.2 billion was set in 2005.