Two of three groups of expert hurricane researchers have already predicted a below-average hurricane season for 2015, and the third has also signaled that an updated forecast due to be released on Monday will confirm the same result.
“The environment is as nonconducive for hurricanes as we’ve ever seen,” Colorado State University Research Scientist Phil Klotzbach told a crowd of about 150 actuaries at a session titled “Predicting Hurricanes” at the Casualty Actuarial Society Spring Meeting in Colorado Springs last month.
Klotzbach said that CSU’s annual benchmark forecast for Atlantic hurricanes is unlikely to change significantly when it is updated June 1.
Every April, Colorado State forecasts the number of tropical storms, hurricanes and severe hurricanes for the June-to-November season, then makes updates in early June, July and August. The 2015 forecast of storms is likely to increase by one, Klotzbach said, to account for May’s Tropical Storm Ana.
Updating the prediction for Ana would mean the forecast predicts eight named storms, three hurricanes and one major hurricane with winds of 111 miles per hour or greater.
On May 27, the National Oceanic and Atmospheric Administration and researchers at Tropical Storm Risk separately published similarly forecasts.
NOAA predicted a 70 percent chance of 6-11 named storms during the 2015 Atlantic hurricane season, which officially runs from June 1 through Nov. 30. NOAA also predicted 3-6 hurricanes and two or fewer major hurricanes.
TSR predicted that hurricane activity would be 65 percent below the long-term average, forecasting four hurricanes and one intense hurricane (Category 3-5) among 10 tropical storms.
The 65-year climate norm would have six hurricanes and three intense hurricanes among 11 named storms, according to TSR.
“Should this forecast verify it will mean that the ACE [Accumulated Cyclone Energy Index] total for 2013-2015 is easily the lower three-year ACE total since 1992-1994, and it would imply that the active phase for Atlantic hurricane activity which began in 1995 has likely ended,” TSR said.
Still, CSU’s Klotzbach said that other active storm eras have had fallow periods like this one. And he noted that the active/inactive rubric really doesn’t apply to storms forming in the Gulf of Mexico or hitting the Gulf States. Storms that form in the Gulf are governed by a different dynamic.
“Your odds of Gulf landfall and Gulf formation don’t really change” in an inactive period, he said. The odds of landfall decrease significantly along the Florida Peninsula and East Coast, however, he said.
In a statement about NOAA’s forecast, NOAA Administrator Kathryn Sullivan noted that below-normal seasons can produce catastrophic impacts, highlighting 1992, when Hurricane Andrew led a season of just seven named storms.
Insurance Analysts Review the Data
While the climate scientists point to the impact of a strong El Nino as the key factor suppressing the hurricane season outlooks this year, insurance analysts Alan Zimmermann and William Wilt of Assured Research, looking purely at data on hurricanes for the last 100 years, provide the following observations:
- Every year in the past 100 has had at least one hurricane. The range has been 1 to 15.
- The most frequent number of hurricanes in a year has been four. Eighteen of 100 years had four hurricanes.
- The number of annual hurricanes has been steadily rising but the percentage striking the U.S. has fallen. As a result, the number of U.S. landfalling hurricanes has remained reasonably constant over successive 10-year rolling periods.
- Of the 561 hurricanes recorded in 100 years, 238—or 42 percent—have been intense (Category 3-5).
- A 100-year annual average is between five and six hurricanes, and between two and three intense hurricanes
- 44 percent of all landfalling U.S. hurricanes have hit Florida, mainly on the West Coast of Florida.
- Hurricanes have hit the state of Florida in 54 of the last 100 years.
- There is no difference in the intensity of storms hitting Florida and other states.
The last named storm to make landfall in Florida was Hurricane Wilma on Oct. 24, 2005. “That the longest nonactive stretch in the last 100 years,” Zimmermann and Wilt report, noting that the odds of nine-year respite given the history is less than 1 percent.
Assured Research and Fitch Ratings gave added some thoughts on insurance and reinsurance market implications last week as well.
“If there are no significant landfalling hurricanes, prices probably continue to weaken and traditional (re)insurers accelerate their return of capital to shareholders,” Zimmermann and Wilt wrote in a their May 2015 research note, repeating a prediction they made in May 2014.
On the other hand, a moderate or bad season—above the current meteorological forecasts but consistent with “model scenarios” of the catastrophe models used by insurers and reinsurers—could stabilize prices or slow the pace of declines.
Only a bad season that reveals catastrophe model flaws could prompt price hikes, the two analysts wrote. And a serious market turn won’t happen “short of some event that is even above extreme tail-risk comprehension,” they said.
Fitch Ratings, noting “current substantial level of industry capitalization,” commented on the level of storm activity that could prompt a negative P/C sector outlook tied to catastrophe experience. “It would likely take a record individual storm loss or a series of significant losses equal to 15 percent or more of industry aggregate surplus” to consider such a move, Fitch said.