... In Search of Severe Weather: Gustav whipped up by deep waters of the Loop

Monday, September 1, 2008

Gustav whipped up by deep waters of the Loop - and more hurricanes on the way

Gustav whipped up by deep waters of the Loop - and more hurricanes on the way

Hurricane Gustav is a monster that seemed to explode into life from a tropical storm on Friday afternoon to a Category 3 hurricane with winds of 230km/h (125 mph) on Saturday morning. Everything has been perfect for its growth, especially the sea temperature.

The Gulf of Mexico is a notorious breeding ground for tropical storms that feed on a dangerous current of deep, warm water called the Loop.

This sweeps up between the Yucatan Peninsula and Cuba, before looping past the tip of Florida, spinning off eddies of warm water. In 2005, Hurricanes Katrina and Rita became mega-storms as they rode over the Loop, and these waters have been responsible for almost all the worst hurricanes in recent years.

The warm water is like rocket fuel for a hurricane, injecting huge amounts of energy that drive the storm into a fury. As the warm, wet air is sucked into the storm it cools and condenses into huge thunderclouds, unleashing a phenomenal amount of energy that powers the hurricane — an average-sized hurricane has the energy of some 10,000 nuclear warheads.

To make this bomb go off, the hurricane needs waters of at least 26C (79F) — and at the moment the waters of the Loop are around 29C (85F). Because the warm waters in the Loop run far deeper than most tropical seas, this gives hurricane a deep reservoir of warm water to feed off even as it churns up the sea with its winds.

Gustav has had a lucky ride in other respects. There is little dry air around to choke it off, and high-level winds, which might otherwise decapitate the storm, have been very calm. High pressure in the upper levels of the atmosphere is also acting like a car exhaust, venting waste air from the top of the storm.

High pressure is also helping steer the storm towards Louisiana, and as Gustav charges across the sea its ferocious winds and low pressure are heaping up a vast bulge of water that will smash into the coastline as a storm surge — the phenomenon that led to the catastrophic floods of Katrina.

In so many ways, this is the perfect recipe for disaster. But forecasters had warned that this was going to be a bad hurricane season, with up to ten hurricanes expected. So far we have had only two, although this was an unusually active start to the season, and in August, Tropical Storm Kay set a new record by making four separate landfalls in Florida, each time blowing out to sea where it recharged before battering the coast again and causing disastrous floods.

Apart from Gustav, there are more problems on the way. Out in the Atlantic, Hanna is about to hit the Bahamas and then may push off to the north and strike eastern parts of the US. More storms are queuing up in the Atlantic’s “Hurricane Alley”, with two areas of concern that could turn into full-blown tropical storms later this week. With another three months of the official hurricane season left to run, this could be a very stormy period.

Whether global warming can be blamed for the surge in hurricanes in recent years is hotly debated. There is a natural cycle in hurricane activity in the Atlantic and Caribbean that goes round every 20 to 50 years, and we are in a very active phase of that cycle. But on top of that natural variability some scientists believe that warmer seas are fuelling more, or more powerful, hurricanes.

USA. Great Lakes Coast Guard units prepare to support Gulf Coast

Sunday, 31 August 2008

Ninth Coast Guard District resources are mobilizing and preparing, Sunday, for deployments to the Gulf Coast as Hurricane Gustav gains strength.

Great Lakes-based Coast Guard units, including some that participated in Hurricane Katrina response operations, are ready to deploy to the region as Gustav's path and strength are monitored.

U.S. Coast Guard Air Station Traverse City, Mich., will deploy an HH-65C Dolphin helicopter to Jacksonville, Fla., and Ninth District support staff members are scheduled to deploy to Mobile, Ala.

An additional Dolphin from Air Station Detroit and members of the Ninth District Incident Management Team stand-by and are ready to respond. The IMT is a group of Coast Guard members who specialize in the management of disaster assistance and emergency response.

The deploying units are prepared to work with Coast Guard units from around the nation, in addition to the numerous Federal, state, local and volunteer responders.

"Similar to Katrina, we are preparing for the worst," said Lt. David French, Ninth Coast Guard District External Affairs Officer. "Our Coast Guard responders remain 'Always Ready' to assist the American public.

"Our hearts and prayers are with the residents of the Gulf Coast and the multi-agency responders who are preparing to assist the region," French added.

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