Forecasters fear busy hurricane season

More hurricanes are likely to beat up the US coast this summer compared to last year, when they stayed at sea, according to top windstorm watchers.

Tropical Storm Risk (TSR), which provides real-time mapping and prediction of tropical cyclone windfields, and is co-sponsored by Lloyd’s broker Aon Benfield, has released its outlook in time for the start of the season on 1 June.

TSR anticipates Atlantic basin and US landfalling hurricane activity being 25% above the long-term (1950-2010) norm.

Importantly for homeowners and businesses in hurricane exposed states like Florida and Louisiana, TSR says that there is a 59% probability of above-normal US landfalling activity and only a 15% chance of a below normal season.

It expects four tropical strikes on the US, including two hurricanes, which compares to long-term norms of three and 1.5 respectively.

Forecasters agreed on outlook

The latest news from the Climate Prediction Centre, a unit of the National Oceanic Atmospheric Administration (NOAA) agrees that this year’s wind season is likely to be worse than last year’s.
NOAA is predicting 12 to 18 named storms (winds of 39mph or higher) of which six to 10 could become hurricanes and three to six major hurricanes. That compares with last year’s 11 named storms, six hurricanes and two major hurricanes.

NOAA’s seasonal outlook doesn’t predict whether the hurricanes will make landfall saying it depends on the weather patterns in place at the time.

Back in April, Colorado State University’s Department of Atmospheric Science said that the probability of at least one major hurricane coming ashore somewhere on the US coast is 72%, compared to the long-term average of 52%.

“The US was fortunate last year. Winds steered most of the season’s tropical storms and all hurricanes away from our coastlines,” noted Jane Lubchenco, under-secretary of commerce for oceans and atmosphere and NOAA administrator. “However we can’t count on luck to get us through this season. We need to be prepared, especially with this above-normal outlook.”
The climate factors that scientists use in formulating an outlook include the Atlantic ocean surface temperature. Sea surface temperatures are often up 2 degrees Fahrenheit higher than average where storms develop.
There’s also the so-called “tropical multi-decadal signal” that brings ocean and atmospheric conditions together and produces more hurricane activity.
Lastly, the sign and strength of the El Niño southern oscillation, a period of abnormally warm sea surface temperatures in the eastern half of the equatorial Pacific, has a strong influence. El Niño conditions are believed to suppress hurricane activity (see sidebar).

US on hurricane watch

“In addition to multiple climate factors, seasonal climate models also indicate an above-normal season is likely, and even suggest we could see activity comparable to some of the active seasons since 1995,” Gerry Bell, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, believes.

Professor Mark Saunders at Tropical Storm Risk agrees that all the main climate indicators point to the 2011 hurricane season being more active for US landfalling activity than 2010. “If a major hurricane does not strike the US in 2011 it will be the first occasion going back to at least 1900 where six consecutive years have passed without such an event."

Let’s hope that’s the case.
Windstorms, or more accurately typhoons, have already wreaked havoc across the US. Tornadoes in April left a trail of destruction that could cost insurers as much as $6 billion. The tornado that left over 100 people dead in Joplin, Missouri could cost insurers as much as $3 billion.

Record first quarter catastrophe losses are reflected in recent earnings announcements from reinsurers, many of which point to prices going up as a result.

Lloyd’s CEO Richard Ward recently warned that the next big natural catastrophe will hit the industry’s capital, not just earnings, unless rates rise significantly.

“For the last two years we have been lucky,” Dr Ward said at an industry conference recently. “Despite some highly active seasons – last year 12 hurricanes formed - none made landfall in the US. At some point our luck will run out.”

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