Other new research showed that global warming produced about half of the extra hurricane-fueled warmth in the North Atlantic in 2005, and natural cycles were a minor factor, according to Kevin Trenberth and Dennis Shea of the National Center for Atmospheric Research, a research lab sponsored by the National Science Foundation and universities.

The academy had been asked to report to Congress on how researchers drew conclusions about the Earth's climate going back thousands of years, before data was available from modern scientific instruments. The academy convened a panel of 12 climate experts, chaired by Gerald North, a geosciences professor at Texas A&M University, to look at the "proxy" evidence before then, such as tree rings, corals, marine and lake sediments, ice cores, boreholes and glaciers.

Combining that information gave the panel "a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years," the panel wrote. It said the "recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia," though it was relatively warm around the year 1000 followed by a "Little Ice Age" from about 1500 to 1850.

Their conclusions were meant to address, and they lent credibility to, a well-known graphic among climate researchers - a "hockey-stick" chart that climate scientists Michael Mann, Raymond Bradley and Malcolm Hughes created in the late 1990s to show the Northern Hemisphere was the warmest it has been in 2,000 years.

It had compared the sharp curve of the hockey blade to the recent uptick in temperatures - a 1 degree rise in global average surface temperatures in the Northern Hemisphere during the 20th century - and the stick's long shaft to centuries of previous climate stability.

That research is "likely" true and is supported by more recent data, said John "Mike" Wallace, an atmospheric sciences professor at the University of Washington and a panel member.

Rep. Sherwood Boehlert, R-N.Y., chairman of the House Science Committee, had asked the academy for the report last year after the House Energy and Commerce Committee chairman, Rep. Joe Barton, R-Texas, launched an investigation of the three climate scientists.

The Bush administration has maintained that the threat from global warming is not severe enough to warrant new pollution controls that the White House says would have cost 5 million Americans their jobs.

"This report shows the value of Congress handling scientific disputes by asking scientists to give us guidance," Boehlert said Thursday. "There is nothing in this report that should raise any doubts about the broad scientific consensus on global climate change.''

The academy panel said it had less confidence in the evidence of temperatures before 1600.

But it considered the evidence reliable enough to conclude there were sharp spikes in carbon dioxide and methane, the two major "greenhouse" gases blamed for trapping heat in the atmosphere, beginning in the 20th century, after remaining fairly level for 12,000 years.

Between 1 A.D. and 1850, volcanic eruptions and solar fluctuations had the biggest effects on climate. But those temperature changes "were much less pronounced than the warming due to greenhouse gas" levels by pollution since the mid-19th century, the panel said.

The National Academy of Sciences is a private organization chartered by Congress to advise the government of scientific matters.

"This one of the very few land areas on Earth where the only thing that separates tropical moisture from polar cold is a barbed-wire fence," said Virginia's state climatologist, Patrick J. Michaels. "Most other places on Earth have a transverse mountain range that separates these two wildly energetic air masses."

The reason the U.S. is the target for so much weather mayhem is that, "We bring together the environmental conditions that will produce severe weather more often than any other place on the planet," said Harold Brooks, a research meteorologist with NOAA's National Severe Storms Laboratory in Norman, Okla.

The U.S. is big -- the world's third-largest country by area after Russia and Canada -- making it a target for weather systems.

The U.S. also lies in the Northern Hemisphere's middle latitudes, where the upper atmosphere's jet stream helps whip up storms and steer them from west to east across the country.

Meanwhile, in contrast to most of the rest of the world, mountain ranges in the U.S. run more or less north-south, not east-west like the chains of mountains girdling Europe and Asia.

The clash of warm, damp air with cold, dry air is the basic recipe for what are called extratropical cyclones, the systems that produce the U.S.'s winter snow and ice storms, and thunderstorms and tornadoes in spring and fall.

And the Rockies and the Appalachians, by spinning the air flowing over those mountains, create spawning grounds for high-impact storms on their eastern sides, said James Hoke, director of NOAA's Hydrometeorological Prediction Center in Camp Springs, Md.

Then there are hurricanes.

"We have an open door through the Caribbean Sea and the Atlantic Ocean to tropics, so that the United States is typically impacted at least once in a hurricane season by a tropical storm or hurricane," said warning coordination meteorologist Bill Sammler at the Wakefield Weather Forecast Office.

Living cheek-by-jowl with the steamy tropics -- and the Gulf Stream along the Atlantic coast also provides moisture for extratropical storms to put to work in heavy snows, flooding rains, explosive thunderstorms and raging tornadoes, Sammler said.

But Hoke said, "we have some of the best weather in the world, almost for the same reasons."

The city of Norwalk, 60 miles southeast of Toledo, was split in two by the flooding. Twenty homes were evacuated and emergency crews were working around the clock to rescue stranded people, Mayor Sue Lesch said.

In Toledo, firefighters resorted to rubber boats to rescue motorists from flooded underpasses, said Lucas County EMA Director William Halsey.

Emergency officials who took damage calls in Ohio said no injuries had been reported, but flood warnings were extended into Thursday there and in southwest Pennsylvania as the rain moved eastward. Water more than a foot deep kept several major roads closed in the Toledo area.

"It hasn't stopped," Ottawa County sheriff's Deputy Jennifer Mansor said Thursday morning. The Ohio Department of Transportation was closing some state routes in the county because of the storm and rising water, she said.

In western Pennsylvania, about 2,000 people were without power early Thursday, and a lightning strike was blamed for a Pittsburgh apartment fire. No one was injured in the blaze.

The storm spawned at least two tornadoes in Michigan, one near Manitou Beach and another near Lambertville, just north of the Ohio line. No injuries or major damage were reported, officials said, but about 40,000 people lost power.

At Magruder Hospital in Port Clinton, between Toledo and Norwalk, the staff had to use generators for a short time after the power went out, and pumps were brought in to remove several inches of water from the front entrance and lobby, supervisor Nancy Merk said.

Lightning danced around Jacobs Field in Cleveland and thunder shook the ballpark as a storm rolled in off Lake Erie, halting the Indians' game against the Chicago Cubs after seven innings Wednesday. Fans retreated underneath overhangs to stay dry during the rain delay and listened to the Doors' "Riders On The Storm" over the loudspeakers.

"We had a domino effect," Gonzalez told the Lubbock Avalanche-Journal in Friday editions. "We had crashes from the Hockley County line to five miles north of Brownfield."

James Brown, 71, of Lubbock, was killed when his car crashed into a tow truck that had stopped to assist with an accident, authorities said.

Twelve people involved in other wrecks were taken to area hospitals, but the extent of their injuries was unknown.

The National Weather Service reported wind gusts at 60 mph in Lubbock and 70 mph in other areas of the South Plains.

If the blaze crosses the northern line crews are building and continues up the edge of Oak Creek Canyon, the next possible place to stop it is 2 1/2 miles to the north, said Paul Broyles, commander of the 700-member firefighting crew.

"Today's a critical day," Broyles said early Thursday. "I won't say it's a last ditch, but there's lot of potential. This is our good shot."

The fire was approaching Slide Rock State Park, a popular recreation spot that draws hundreds of thousands of visitors a year.

"Things are going well out there," said Larry Sears, a divisional commander. "Now we need to get to that north side and find a good place to hold it."

The blaze started Sunday in a camp used by transients and spread quickly, forcing evacuations in the canyon 90 miles north of Phoenix. The Forest Service is offering a reward up to $5,000 for information leading to a conviction of those responsible for the fire.

Mike Yeager has a home in the lushly forested canyon, whose walls are tinted crimson by iron oxide.

"It makes me so mad. I just want to spit," he said. "These people started a fire in the most beautiful place in the world."

In Colorado, favorable weather conditions helped firefighters hoping to expand containment lines around a wildfire that has forced residents from 300 homes. No houses have been lost, but U.S. 160, a major thoroughfare, remained closed for a fourth day about 150 miles south of Denver.

The same weather that was helping keep the flames in check also kept the highway closed, fire information officer Steve Segin said. Fire managers need to burn off nearby vegetation that could ignite should the wildfire return that way, but the weather was too damp to keep a backfire burning.

"We're desperately trying to do that to get the highway open," Segin said.

Citing dangerously dry conditions, Gov. Bill Owens issued an order Wednesday banning open burning and fireworks on all state-owned land and urged local officials to do the same.

In New Mexico, heat, wind and rugged terrain slowed efforts to control fires that have burned nearly 70,000 acres of forest.

The largest blaze, burning across about 33,250 acres in southwestern New Mexico, continued to threaten cabins in the Willow Creek area, fire officials warned.

In California, firefighters battled a blaze of more than 13,000 acres that had stopped short of a critical ridgeline in Los Padres National Forest. No homes were threatened as the fire burned away from the small town of New Cuyama, about 45 miles east of Santa Maria.

Wildfires have charred nearly 3.2 million acres nationwide so far this year, well ahead of the average of just over 1 million acres by this time, the National Interagency Fire Center reported. Huge grass fires that swept Texas and Oklahoma this spring account for much of the increase.

"Rescuers say most of the missing people are likely to have been swept out to sea," said Ode Parmodes, also of the relief office.

The flash floods and landslides were triggered by incessant rains since Monday, and the government has promised an investigation into claims that illegal logging may have been a contributory factor.

"What has happened in Sinjai should become a lesson to all of Indonesia: people must be alert if torrential rains pour over areas where forests have been depleted," said Forestry Minister Malam Kaban.

Hundreds of people flocked to hospitals to look for missing relatives, witnesses said.

One man, Rohim, said a flood tore through his house early Tuesday, sweeping him out to sea. He said he survived for nine hours by hanging onto a piece of drift wood, but his wife and two sons had vanished.

"I pray for them, and hope rescuers can find them," he said at Sinjai hospital, where he had been looking for their bodies in the morgue. "I will stay here until I can find them: dead or alive."

Sulawesi is about 1,000 miles northeast of Indonesia's capital, Jakarta.

Seasonal downpours cause dozens of landslides and flash floods each year in Indonesia, where millions of people live in mountainous regions and near fertile flood plains close to rivers. Some environmentalists and government officials blame rampant deforestation, which they contend loosens soils on mountainsides.

"There are spills everywhere, especially around the Chechen capital Grozny," said the official from the agency known as Rosprirodnadzor.

WWF's Yelena Kulikova said that the dense mountain forests of Chechnya and elsewhere in Russia's North Caucasus region were "also in danger because of illegal logging," the AFP reported.

Just four Rosprirodnadzor forest wardens are deployed in Chechnya, where sporadic fighting continues 11 years after Russian troops were first deployed to crush a separatist uprising by Muslim Chechens, officials said.

"We have seen serious environmental problems around Grozny where there are frequently landmines and where already last year (three forest guards) died," forestry commission deputy director Mikhail Guiryayev said.

Oilfields in the tiny province have been exploited for years in an unregulated and often criminalized industry, while Russian bombing and shelling has reduced former factories, refineries and tens of thousands of dwellings across Chechnya to ruins.

The forested areas have also been subjected to years of bombardments and sown with landmines.

Empedocles is dormant and shows no sign of imminent eruption. Mount Etna, Europe's largest active volcano, lies 100 km (62 miles) to its north.

Empedocles' base measures 750 square km and stands 400m (2460 ft) high.

At various times in history, the volcano has formed a small island.

The first recorded eruptions occurred in the third century BC and the last in 1831.

Its emergence then put it at the centre of an international row over who the volcano actually belonged to.

New survey equipment has confirmed that what used to be considered a series of small underwater fissures are in fact part of a single massive volcano.

"People used to think that there were small centres of emission, distant from each other," Cesare Corselli, president of the National Inter-University Consortium for Marine Science, was quoted by Reuters news agency as saying.

"The hypothesis... is that this is a singular volcano that, alongside Etna as an example, can have a central eruption or a series of lateral eruptions," he said.

The volcano was named Empedocles after the Greek philosopher who hypothesised that all matter consisted of four elements - earth, air, fire and water.