US hurricane drought is 'basically dumb luck', scientists say

http://www.theguardian.com/world/2015/apr/30/us-hurricane-drought-dumb-luck-katrina-wilma

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Ten years ago, an especially strong and destructive hurricane season brought Katrina to Louisiana in August, followed two months later by Wilma slamming into the Florida coast. And then, for the next 10 years, nothing: no major hurricanes have hit the United States since.

As the US approaches another hurricane season beginning on 1 June, it will also be approaching a historic milestone: there have been no category 3 or above hurricanes in nearly a decade, a stroke of luck that scientists say is truly out of the ordinary.

This current “hurricane drought” is the longest ever recorded since scientists began keeping track of hurricanes in 1851. The last record of eight years happened from 1861–68.

New research from Nasa’s Goddard Institute for Space Studies, published this week in Geophysical Research Letters, suggests the historic drought is probably just a coincidence.

“We concluded it’s basically dumb luck,” said co-author of the report and senior scientist at Nasa’s Goddard Institute Dr Timothy Hall. “If [the drought] went on and on and on we’d question our assumptions, but for now it seems to be luck.”

There have been plenty of major storms and hurricanes since 2005, but all major hurricanes have missed the US and instead concentrated on other regions around the Atlantic Ocean. And there have been more minor storms that were nonetheless destructive within the US: Hurricane Sandy in 2012 (category 1), Hurricane Irene in 2011 (category 1) and Hurricane Ike in 2008 (category 2).

Most of the damage from those storms came from rain and subsequent flooding (partially exacerbated by sea-level rise and storm surge).

Hall said the lack of major wind damage from hurricanes in the last decade could have serious consequences if people are lulled into a sense of complacency about extreme weather.

Hall’s study, carried out with Kelly Hereid from ACE Tempest RE, a reinsurance firm, found that insurance rates were falling in hurricane-prone areas, and people were flocking to the coasts – meaning there could be more damage when a major hurricane eventually makes landfall.