Forecasts calling 2015 possibly one of the least active hurricane seasons of the 20th century may eventually lead to a call that the North Atlantic has entered a “inactive era,” a multidecadal cycle that would see the number of storms decrease.
“If our forecast verifies this year, and we have three inactive seasons in a row (given that 2013 and 2014 were also quiet), it would likely mean that we were moving into an inactive era,” says Philip J. Klotzbach, Ph.D., researcher at Colorado State University‘s Tropical Meteorology Project. “Inactive eras have tended to last 20-30 years. Of course, you can still get active seasons in inactive periods.”
Hurricane eras switch between active and inactive phase that last two to three decades, according to research from the National Oceanic and Atmospheric Administration (NOAA). The U.S. is currently in the 20th year of an active phase that began in 1995.
Klotzbach adds that it is difficult to say how a possible inactive hurricane will manifest itself, or if it would resemble previous low activity era.
“We’d only be three years into an inactive era, so too hard to say which one it looks most like,” he said, adding that for reinsurers and insurers anticipating a multi decade cycle of lower storm activity should not necessarily expect it to translate into lower losses.
“Inactive Atlantic seasons don’t always agree with landfall numbers. Even though since 2005 has generally been active for the Atlantic as a whole, we have had no major hurricane landfalls since Wilma in 2005,” Klotzbach adds. “ There is always “hurricane amnesia” that occurs whenever you go long periods of time without landfalls.
Klotzbach and William M. Gray, Ph.D., issued their extended range forecast for the 2015 Atlantic Hurricane season, calling for 3 hurricanes , 7 named storms and a probability of U.S. major hurricane landfall estimated at about 55 percent of the long-period average.
“We anticipate that the 2015 Atlantic basin hurricane season will be one of the least active seasons since the middle of the 20th century. It appears quite likely that an El Niño of at least moderate strength will develop this summer and fall.” the report states. “The tropical and subtropical Atlantic are also quite cool at present. We anticipate a below-average probability for major hurricanes making landfall along the United States coastline and in the Caribbean.”