* Climate change could fuel tornado-making storms
* 2011's disasters caught insurers off guard
By Deborah Zabarenko
WASHINGTON, Feb 22 One year after a deadly
tornado season in the United States caused nearly $30 billion in
damage, an above-normal number of twisters could be in store for
While there is no way to predict that there will be a repeat
of 2011's calamitous series of tornadoes, private weather
forecaster Accuweather.com said this week there are likely to be
more tornadoes than normal across the United States.
Climate change is indirectly related to this forecast
because strong thunderstorms create conditions where tornadoes
can form, and strong thunderstorms could be fueled by the
warmer-than-normal surface waters of the Gulf of Mexico,
according to Paul Walker, senior meteorologist at Accuweather.
Tornadoes caused $28.7 billion in damage in the United
States in 2011, and killed more than 550 people, the U.S.
National Climatic Data Center found.
One reason the loss of life and financial toll were so high
last year was because some of the most severe tornadoes hit
populated areas, notably Joplin, Missouri, and Birmingham,
Alabama, Walker said.
This may have been caused by a strong La Nina pattern, which
can shift "Tornado Alley" eastward from its normal span in the
plains of Kansas, Oklahoma and Texas.
La Nina starts as a cool patch of water in the equatorial
Pacific that can have a global weather impact; El Nino is a warm
swathe of water in the same area. There is little sign of a
strong La Nina or El Nino this year, Accuweather said.
Total U.S. damage in 2011 from climate and weather
disasters, including drought, was $55 billion. Floods along the
Mississippi and the upper Midwest cost an estimated $5 billion
damage and claimed at least 12 lives, according to the National
Climatic Data Center.
If taken as a single event, last year's spring tornado
season would have been the fourth-costliest disaster in U.S.
history from an insurance perspective, behind hurricanes Katrina
and Andrew and the Sept. 11, 2001, attacks on the United States.
A new study suggests climate change could cause more
flooding as storm surges - the damaging masses of water
propelled inland by hurricanes and other storms - become more
Floods that have been expected once a century could happen
every three to 20 years, researchers from Princeton University
and the Massachusetts Institute of Technology reported in the
latest issue of Nature Climate Change.
Such sharp changes in climate could force insurers to
reconsider the losses they face. If such one-in-100-years storms
start occurring every 20 years or less, it may lead insurers to
reduce their exposure to certain regions or charge substantially
more for coverage.
(Additional reporting by Ben Berkowitz; Editing by Vicki Allen)