August Busiest Month for Hurricanes

August 11, 2010

While the National Oceanic and Atmospheric Administration (NOAA) has slightly amended the hurricane outlook it released in May, an above-normal season is still expected. With ocean temperatures at record highs, and the climate phenomenon known as “La Nina” beginning to development, government forecasters maintain that this may be the busiest Atlantic hurricane season since 2005.

The original forecast predicted 14-23 named tropical storms during this hurricane season. Those numbers have been revised to a range of 14-20. The Atlantic hurricane season began on June 1st, and runs through November 30th, but the peak period is in high summer and early fall: August through October, during which eight to twelve storms could develop into hurricanes, four-to-six of which could evolve into “major storms” with winds in excess of 111 mph.

Jane Lubchenco said in a statement to the press, “August heralds the start of the most active phase of the Atlantic hurricane season and with the meteorological factors in place, now is the time for everyone living in hurricane prone areas to be prepared.”

Historically during active storm seasons, multiple hurricane strikes are much more likely for both the Gulf Coast and the East Coast in the U.S., but the Caribbean also sees a marked increase in the number and severity of storms during active seasons. This could mean bad news for Haiti, where there are roughly 1.6 million people still living under tarps and in tents, seven months after a disastrous earthquake crumbled its capital.

So far this season, three named storms have developed. Hurricane Alex made landfall in northern Mexico on June 30th, and tropical storm Bonnie caused some trouble for oil company crews working in the Gulf of Mexico in July. Last Thursday, tropical storm Colin regenerated, with winds of 45 mph over the open Atlantic, according to the National Hurricane Center in Miami, FL. A tropical storm warning was issued for Bermuda.

According to Gerry Bell, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center in Washington, the May outlook, which called for eight to 14 hurricanes, with possibly three to seven major hurricanes, reflected a more active early summer than we actually had. Bell also said that the update is based on indications that a high-activity era which began in 1995 is continuing.

“The atmospheric and oceanic conditions now in place are very conducive to hurricane formation, as we had predicted in May,” he said.

A Pacific Ocean phenomenon called La Nina developed in July, reducing wind shear in the Atlantic and making it easier for storms to take shape. As well, ocean temperatures are exceptionally high, and the warmest since 2005 when Hurricanes Katrina and Rita tore apart the very part of the Gulf of Mexico now dealing with BP’s oil spill. According to Bell, during above-normal seasons it’s typical for three named storms to spin into the Gulf between August and November. A storm’s individual strength and its path across the water would determine whether there would be any impact on remaining oil from the explosion last April.

Tropical storms are named when sustained wind speeds reach 39 mph (62 kph). They become hurricanes when sustained winds reach 74 mph (119 kph). Major hurricanes blow at 111 mph (178 kph) or more. The strongest hurricanes are labeled Category 5, with winds greater than 155 mph (250 kph).

Last week, researchers from Colorado State University researchers said they also expected this year’s season to be more active than average, forecasting 10 hurricanes, five of them major.

Hurricane season ends Nov. 30.