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Currently showing: Climate/natural disasters > Disaster risk

24 Apr 17 14:25

It's said there are two things that are inevitable in life – death and taxes. Yet in my chosen field of meteorology there's something else that could be added to that list: The Colorado State University (CSU) Atlantic Hurricane season outlook. Regular as clockwork every April.

And so just as I wrote my annual check to the Internal Revenue Service, the CSU forecast was released calling for slightly below average activity in the Atlantic, with 11 named storms, four hurricanes and two major hurricanes being forecast.

The reasons for CSU's forecast for a slower season? The possibility of a weak to moderate El Nino by the peak of hurricane season, which tends to suppress hurricane activity in the Atlantic, and an Atlantic Ocean that has unexpectedly cooled off in the last few months and are running at about average temperatures. 

The Gulf of Mexico, particularly the western Gulf, is about 1 – 2 °C above average, and didn't fall below 73 degrees Celsius all winter. There is low correlation between the seasonal hurricane activity in the Atlantic and Gulf of Mexico sea surface temperatures, simply because for the most part, tropical waves actually have to make it to the Gulf of Mexico. If conditions are hostile in the open Atlantic, most waves will be destroyed and sheared apart by the time they make it far enough west into the Gulf.

That being said, should a tropical wave make it there intact, and the atmospheric conditions are right, there is plenty of heat in the Gulf of Mexico to promote strengthening, even rapid intensification. And given that nearly all hurricanes in the Gulf have to make landfall somewhere, that area will be one to watch this summer.

The US is entering its 12th hurricane season without a major hurricane making landfall along its coast; Matthew came close, but weakened prior to landfall in South Carolina as a category 1 hurricane. However, as I discussed in my blog at the start of hurricane season last year, it no longer takes a major hurricane to cause a major disaster.

Additionally, CSU's forecast for a less-than-active season shouldn't give way to the false sense of complacency that there is no risk to those living in hurricane-prone areas. It only takes one storm, forming in the right place, at the right time, under the right set of conditions to upend people's properties, business and lives. Similar to the forecast for this year, the 1989 hurricane season produced 11 named storms, 2 of which became major hurricanes. One of those two major hurricanes was Hurricane Hugo, which made landfall in South Carolina as a Category 4 hurricane and became the US's first $1 billion insured hurricane loss. Thus, it's never too early nor too cautious to begin preparing and planning for hurricane season, regardless of the forecast.

Category: Climate/natural disasters: Disaster risk, Floods/storms, Resilience

Location: United States


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