At least 221 people have died during a cold snap in which temperatures have plummeted to -30C and below across eastern Europe, with Ukraine the hardest hit country.

The cold has killed 101 people in Ukraine, many of whom lived on the streets. Health officials have ordered hospitals to stop discharging homeless patients after they are treated for hypothermia and frostbite, while authorities have set up nearly 3,000 heating and food shelters to help people survive. The week-long cold snap, eastern Europe's worst in decades, is causing power cuts, frozen water pipes and the widespread closure of schools, nurseries, airports and bus routes.

Officials reported a total of 600 flight cancellations at Denver International Airport, while Southwest Airlines canceled all inbound flights to Denver until 1 p.m. local time. Denver's airport -- which was reporting 5 inches of snow as of 10:45 a.m. -- deals with an average of 1,700 flights daily, according to airport spokeswoman Jenny Schiavone. Light snow started falling in Denver Thursday as residents across the state braced for the storm.

Scientists have known for decades that hidden under those impressive vistas at sites such as Death Valley and Yellowstone National Park are magma pools that under the right conditions can trigger explosive eruptions.

Now, new research is changing scientists' understanding of the timing of those eruptions, and prompting them to call for greater monitoring of sites to help save lives when the next big volcano explodes.

Two recent papers highlight the shift. One looked at a Death Valley volcano thought to be 10,000 years old and found it last erupted just 800 years ago, and is still an eruption danger. The other found that large caldera volcanoes, such as the one under Crater Lake in Oregon, can recharge in a matter of decades, rather than the thousands of years previously thought.

The sun is gearing up for a peak in activity at a time when technology makes our planet more vulnerable to solar outbursts than ever before. Monitoring has improved since the last solar maximum, so what are the big risks this time around?

About once every 11 years, the sun goes ballistic, throwing out more bursts of magnetic activity than normal. As a large but harmless solar flare signalled last week, the next solar maximum is due in 2013.

In the past, these storms have triggered extra currents in power lines, destroying transformers and leading to blackouts. This time around, blackouts could be more common. John Kappenman of Storm Analysis Consultants in Duluth, Minnesota, found that many transformers in the US are ageing and therefore extra fragile.

A Blast from the past has left fascinating hints that volcanic eruptions could be predicted several decades in advance. Volcanoes can signal their intent to erupt days or months ahead of time, giving authorities a chance to evacuate and secure the area. Now evidence of the events leading up to a Bronze Age eruption suggests it might be possible to extend that warning period even further.

The Santorini volcano in the Greek islands lay dormant for 18,000 years before blowing its top around 3500 years ago, perhaps contributing to the demise of the Minoan civilisation. A close look at the pumices produced in the eruption shows that Santorini woke up around 100 years earlier. [ns]

The eruption of some of the largest volcanoes on the planet could be predicted several decades before the event, according to researchers.

Analysis of rock crystals from the Greek island of Santorini suggests eruptions are preceded by a fast build-up of magma underground, which might be detected using modern instrumentation. Supervolcanoes can produce enough ash and gas to temporarily change the global climate. [bbc]

Rescue helicopters evacuated dozens of people from snow-blocked villages in Serbia and Bosnia and airlifted in emergency food and medicine as a severe cold spell kept eastern Europe in an icy grip.

The death toll from the cold snap rose to 79 across the region, with emergency crews working overtime as temperatures sank to -32.5C (-26.5F) in some areas. Parts of the Black Sea froze near the Romanian coastline and rare snow fell on Croatian islands in the Adriatic Sea. In Bulgaria, 16 towns recorded their lowest temperatures since records began 100 years ago.  [guardian]

At least 73 people have been killed in clashes between rival fans following a football match in the Egyptian city of Port Said, state television reports. The deaths occurred as supporters invaded the pitch after a match between top-tier clubs Masry and al-Ahly on Wednesday. It is feared the death toll could rise as at least 156 people have been hurt. It is the biggest disaster in the country's football history, said the Egyptian deputy health minister. [bbc]

Research suggests the risks posed to the nation's nuclear reactors may have been underestimated and therefore could be worse than the power plants were designed to withstand.

U.S. nuclear power companies will be directed to reassess their reactors' vulnerability to an elevated threat from earthquakes east of the Rockies, using new computer models and seismic data released today by an industry and government project.  [sciam]

The world is running out of time to make sure there is enough food, water and energy to meet the needs of a rapidly growing population and to avoid sending up to 3 billion people into poverty, a U.N. report warned on Monday.

As the world's population looks set to grow to nearly 9 billion by 2040 from 7 billion now, and the number of middle-class consumers increases by 3 billion over the next 20 years, the demand for resources will rise exponentially. Even by 2030, the world will need at least 50 percent more food, 45 percent more energy and 30 percent more water, according to U.N. estimates, at a time when a changing environment is creating new limits to supply.

A powerful earthquake injured scores of people, buckled buildings and caused power outages on the coast south of Lima early Monday morning, with no immediate reports of fatalities, officials said. Most people were injured when they fled their homes in panic, or when they were struck by collapsing walls.

Up to 200,000 homes in England and Wales have been warned they will struggle to obtain adequate flood insurance after June 2013, when the insurance industry's voluntary flood agreement with the government ends.

In 92 constituencies there are 1,000 or more homes at high flood risk, the Association of British Insurers (ABI) said after analysing the latest Environment Agency flood data.

Boston and Skegness in Lincolnshire is the constituency with the most homes at significant risk of flooding, with 7,550 properties under threat, followed by the Vale of Clwyd (7,339 homes), Folkestone and Hythe (7,196), and Windsor (7,125). A property is defined as being at risk if it has a one in 75 chance of flooding in any given year.

A new international study may answer contentious questions about the onset and persistence of Earth's Little Ice Age, a period of widespread cooling that lasted for hundreds of years until the late 19th century.

The study, led by the University of Colorado Boulder with co-authors at the National Center for Atmospheric Research (NCAR) and other organizations, suggests that an unusual, 50-year-long episode of four massive tropical volcanic eruptions triggered the Little Ice Age between 1275 and 1300 A.D. The persistence of cold summers following the eruptions is best explained by a subsequent expansion of sea ice and a related weakening of Atlantic currents, according to computer simulations conducted for the study.

Asteroid near misses and the threats to come

Figures show about 50 million NEO’s (Near Earth Objects) pass by every day. Here are some previous near misses as well as possible future threats.

Did Princess Diana fake her own death to escape the public eye? Or was she killed by a rogue element of the British secret service?

If you agree with one of these theories, there's a good chance you'll subscribe to both even though one suggests Princess Diana is alive, the other dead, a new study indicates.

It's known that people who believe one conspiracy theory are inclined to endorse others as well. But new research shows that conspiracy theorists aren't put off by contradictory theories and offers a reason why.

"They're explained by the overarching theory that there is some kind of cover-up, that authorities are withholding information from us," said Karen Douglas, a study researcher and reader in the school of psychology sciences at the University of Kent in the United Kingdom. "It's not that people are gullible or silly by having those beliefs. … It all fits into the same picture."

The study says Haiti's 7.0-magnitude earthquake two years ago is likely to be the first of several quakes of a similarly powerful magnitude.

The Jan. 12, 2010, earthquake caused widespread damage in the Haitian capital and surrounding cities. Officials say the disaster killed 314,000 people and toppled thousands of crudely built homes. [yahoo]

Researchers at Michigan State University (MSU) have demonstrated how a new virus evolves, shedding light on how easy it can be for diseases to gain dangerous mutations. The findings appear in the current issue of the journal Science.

The scientists showed for the first time how the virus called "Lambda" evolved to find a new way to attack host cells, an innovation that took four mutations to accomplish. This virus infects bacteria, in particular the common E. coli bacterium. Lambda isn't dangerous to humans, but this research demonstrated how viruses evolve complex and potentially deadly new traits, noted Justin Meyer, MSU graduate student, who co-authored the paper with Richard Lenski, MSU Hannah Distinguished Professor of Microbiology and Molecular Genetics.  [sciday]