As many as six major hurricanes could form in the Atlantic Basin during a busy 2011 summer storm season, forecasters announced today.

Twelve to 18 named tropical storms with winds of at least 39 miles (63 kilometers) an hour could form in the Atlantic Basin, which includes the Gulf of Mexico and the Caribbean Sea, according to National Oceanic and Atmospheric Administration (NOAA) head Jane Lubchenco.

Six to ten of those named storms could intensify into hurricanes—meaning they’d have winds of at least 74 miles (119 kilometers) an hour, Lubchenco said during a press briefing.

Tens of thousands of people fled the path of a cyclone bearing down on northeastern Australia as officials warned it had increased in strength overnight.

Queensland Premier Anna Bligh urged residents of low-lying areas to leave quickly as gusts up to 174 mph were expected ahead of Cyclone Yasi, which was forecast to hit Cairns late Wednesday.

“We are facing a storm of catastrophic proportions in a highly populated area,” Bligh told reporters. “What it all adds up to is a very frightening time. We’re looking at 24 hours of quite terrifying winds, torrential rain, likely loss of electricity and mobile phones.”

The 2010 Atlantic hurricane season was forecasted to be a busy one, and so far it has lived up to the expectations. Halfway through the season, the number of tropical storms and hurricanes has almost equaled the average totals for an entire season. Fortunately, we have yet to experience a major disaster comparable to some of the past decades most severe storms, which brought billions of dollars of damage, death and devastation to the regions they bombarded. Here are the eight costliest hurricanes of the 2000s.

1. Katrina $125 billion (2005)

Hurricane Katrina is by far the most devastating natural disaster in modern US history. The storm itself was massive: it was a category 5 with 175 mph winds in the Gulf, though it weakened to a category 3 as it made landfall enough to cause New Orleans levees to fail, flooding up to 80 percent of the city. A great American town was nearly wiped out, and in the process, 1,833 people were killed. People from across the country and world sat in shock as they viewed the now iconic images of people pleading for help from their rooftops and outside of the Superdome. Often overlooked is the fact that the Mississippi Gulf Coast was decimated by the storm surge as well. Katrina caused us to examine every aspect pertaining to how we should deal with hurricanes.

Tropical Storm Karl is bearing down on Mexico, with two dangerous category four hurricanes – Igor and Julia – also sweeping in from the Atlantic. Karl, packing maximum sustained winds of 65mph (100km/h), is close to the Mayan Riviera on Mexico’s Yucatan peninsula. Igor, said to be the season’s most powerful hurricane, is moving west-north-west towards Bermuda. Julia intensified to category four on Wednesday, with winds close to 135mph.

NUEVO LAREDO, Mexico – Mexican authorities opened shelters and warned people to watch out for mudslides Monday as Tropical Storm Hermine approached the northeastern border with Texas, the second major storm to hit the area this season.

Hermine could approach hurricane strength before making landfall early Tuesday in a sparsely populated area about 50 miles (80 kilometers) south of Matamoros, a city bordering Brownsville, Texas, according to the National Hurricane Center in Miami.

A hurricane watch was issued for the area from Rio San Fernando, Mexico, northward to Baffin Bay in Texas.

BUXTON, N.C. – Hurricane Earl packed winds near 140 mph as it blew toward North Carolina on Thursday, putting the Eastern Seaboard up to Maine on alert for a Labor Day weekend pounding by waves, gales and rain.

A hurricane warning for the tip of Massachusetts, including Nantucket and Martha’s Vineyard, joined earlier warnings and watches for hurricanes or tropical storms that stretch from North Carolina up to near the Canadian border.

Earl was a dangerous category 4 storm with no significant change in strength forecast before it comes close to the Outer Banks late Thursday, then turns north in rough parallel to the coast, the National Hurricane Center in Miami said.

The center’s director, Bill Read, said the eye of the storm will likely remain about 30 to 75 miles east of the Outer Banks. At the closest point of approach, the western edge of the eye wall could impact Cape Hatteras, with huge waves, beach erosion and maybe some property damage from the waves.

SAN JUAN, Puerto Rico – Hurricane Earl lashed the northeastern Caribbean on Monday as a still-growing Category 3 storm on a course that could threaten the eastern United States later this week.

The U.S. National Hurricane Center in Miami said Earl, which formed on Sunday, was already a major hurricane with sustained winds of 120 mph (193 kph), and it was likely to keep gaining force.

“Interests from North Carolina all the way to Maine should keep an eye on the system,” said Jessica Schauer, a meteorologist at the Hurricane Center.

The storm’s forecast track would run north of the Caribbean, then bend to the north, roughly parallel to the U.S. East Coast. The hurricane center said it is early to say what effect Earl would have on the U.S.

BEIJING – A typhoon that left scores dead in the Philippines and two in China weakened to a tropical storm as it churned toward northern Vietnam on Saturday, smashing boats in its path and lashing the region with rain and wind. It was expected to make landfall before dark. Authorities said more than 170,000 people were being prepared for evacuation.

China’s state-run Xinhua News Agency said several Vietnamese ships had been wrecked off islands in the South China Sea, but there was no immediate word on whether anyone had died. It quoted a maritime-affairs official on the southern resort island of Hainan, hit Friday, as saying rescue efforts were under way. A man answering the telephone in the maritime bureau said he wasn’t authorized to talk to the media. Typhoon Conson, China’s first typhoon of the year, roared in from the Philippines, where the death toll continued rising Saturday to 65, with 87 missing. Xinhua said a falling billboard killed a motorcycle rider after the storm brushed Hainan, and another toppled and buried a security guard under debris. By 8 a.m. Saturday, Hainan’s meteorological station said Conson was moving northwest over open water again and had weakened into a strong tropical storm. It was expected to hit northern Vietnam by afternoon or evening and was moving at 12 miles an hour.

China is bracing itself for its worst floods in more than a decade as Typhoon Conson closes in on its southern coast.  Conson – which claimed at least 37 lives in the Philippines – brings with it torrential rains increasing the risk of floods, meteorologists warned. Floods and landslides have killed at least 135 people in China this month and 41 are missing, state media report.

More than 35 million people across China have been hit by the poor weather and 1.2 million have been relocated. Conson had been downgraded to a tropical storm after it left the Philippines but strengthened into a typhoon again late on Thursday.The China Meteorological Administration said it was packing winds of 75mph (120km/h). Conson is expected to make landfall late on Friday in Hainan, an island off south-east China, where 24,000 fishing boats have been recalled. Light rain was already falling on Hainan, and conditions were dark and windy, an official at the local meteorological bureau told AP news agency.  Parts of Guangdong province and neighbouring Guangxi region are also forecast to see torrential rains over the next 24 hours.

Tropical Storm Conson rolled westward across the Philippines on Wednesday morning, stranding more than 1,300 people across the archipelago and forcing the Philippine National Disaster Coordinating Council to issue warnings about flash floods, landslides and big waves. Conson made landfall with maximum sustained winds of 69 mph on the northern Philippine island of Luzon, about 41 miles east of the capital, Manila, on Tuesday evening. As of 10 p.m. Tuesday (10 a.m. ET), sustained winds were down to about 59 mph in the center, with gusts up to 74 mph, according to the National Disaster Coordinating Council.