WHY DOES BOILING WATER TURN TO SNOW WHEN IT'S COLD?

The polar vortex means it’s so cold that water will disappear into the air if you throw it – here’s why.

The arrival of a polar vortex in the US means people are once again stepping outside into sub-zero temperatures to throw boiling water into the air.

Since the advent of social media it has become a winter ritual, with videos of the spectacular effect currently blossoming across the internet.

If done correctly, the boiling water blooms into a white cloud as soon as it hits the freezing air, making it appear like it has turned instantly to snow.

But the science behind the phenomenon shows this isn't exactly what is happening. Instead, the hot water is actually evaporating into steam, before condensing into tiny droplets of water that then freeze into a solid state.

Essentially, the very high temperature of the water combined with the very low temperature of the air causes the water to pass through its three states almost instantaneously – from liquid to gas, then to liquid, then to solid. 

It might sound more dramatic that the water is hot – but that makes it more likely to happen. Since the water is warmer it evaporates more quickly, allowing it to turn to steam as soon as it is thrown.

The cold air can't hold that vapour, so almost as soon as that process happens it changes once again into droplets of liquid – which are so small that the air around them causes them to freeze instantly – and turns into a solid.

Because the effect works with boiling water, it is dangerous for anyone who tries it. One person in Madison, Wisconsin was treated for burns after throwing scalding water into the air, local media reported.

Hundreds of videos of the billows have been shared on Twitter and Facebook, though not all attempts have been successful.

The experiment has even been attempted by people with high-powered water pistols.

Temperatures need to be around -30 degrees celsius and below before the trick actually works, so it is unlikely people in the UK will be able to do it despite the current cold snap.Anyone attempting it before the mercury has reached that low risks covering themselves in boiling water.

In freezing temperatures boiling water turns instantly to vapour when it is thrown in the air (YouTube/ Screenshot)

One person in Madison, Wisconsin was treated for burns after throwing scalding water into the air, local media reported.

A spate of accidents also occurred in 2014, following a similar drop in temperatures across the US.

Asia Cold Snap

Asia cold snap: Scores dead as freezing 'polar vortex' sweeps across eastern Asia

By Adam Withnall, 25 January 2016 12:25

Asia's 'polar vortex' has seen some regions hit by their coldest weather for more than half a century

More than 60 people have died as a band of extreme cold weather spread across eastern Asia, stranding tens of thousands of tourists and bringing some regions their lowest temperatures for half a century.

While much international attention has been focussed on the heavy snowfalls in the eastern US, another cold snap has descended over Korea, China, Hong Kong and Japan.

Temperatures dropped across Asia on Sunday due to a deep depression pulling cold weather down from the north. Major Chinese cities like Shanghai and Beijing hit -4/-5, while -18 was recorded in Seoul, South Korea.

Taiwan saw some of the worst impacts, however, because its subtropical geography means most homes are without central heating.

City officials in Taipei said on Monday that temperatures had hit a 16-year low of 4C,well below the average of around 16C. The cold had caused heart trouble, shortness of breath, strokes and hypothermia and accounted for the deaths of at least 57 people in the wider city area.

Up to 3.5 inches of snow blanketed the island’s tallest peak, Jade Mountain. Authorities warned people to keep warm out of the cold after a 56-year-old man was found dead on the street.

In Hong Kong, a low of 3C was recorded – the lowest temperature there in almost 60 years. News headlines about Asia’s “polar vortex” saw hundreds visit mountains around the city expecting snow.

According to the South China Morning Post, the mountains ended up covered not with snow but with underprepared hikers. Police reportedly had to block off roads up to the hills because so many people refused to heed warnings, and some had to be rescued by fire crews.

“We came here to watch snow,” a young man said on NOW TV news. “We are a bit disappointed and freezing.”

A sixth person was reported to have died on Monday after heavy snows left five people dead over the weekend in western and central Japan, including a woman who fell from a roof while removing snow.

Kyodo News service and other local media reported an 88-year-old woman in western Japan's Tottori prefecture died after a landslide hit her house before dawn.

The bullet train service was delayed, while there were flight cancellations across the country.

In South Korea, more than 500 flights were cancelled to the internationally-renowned holiday island of Jeju, known for its year-round balmy weather and beaches.

The mercury there hit -6C on Sunday, while heavy snow closed the airport entirely. An estimated 60,000 tourists were stranded there in total, the BBC reported, though officials said they hoped the runway would be cleared for use by Monday night.

Most parts of mainland China experienced their coldest weather in decades over the weekend. The southern city of Guangzhou, which has a humid subtropical climate, saw snow for the first time since 1967 on Sunday, the city's meteorological service said.

The cold led to at least four deaths — strawberry farmers who died of carbon monoxide poisoning when they turned up heating in a plastic greenhouse, the Xinhua News Agency reported.

The National Meteorological Bureau forecast that temperatures in southern China would drop another 3-8 degrees Celsius on Monday.

Source: https://www.independent.co.uk/news/world/asia/asia-weather-cold-snap-china-south-korea-hong-kong-taiwan-japan-scores-dead-polar-vortex-a6832416.html

Related: https://www.independent.co.uk/life-style/us-polar-vortex-frozen-hair-taylor-scallon-twitter-viral-videos-a8757711.html

Polar Vortex in US

More than 20 dead in US polar vortex, frostbite amputations feared

NEW YORK: Tens of millions of Americans on Thursday (Jan 31) braved Arctic-like temperatures as low as -49 degrees Celsius that paralysed the US Midwest and were blamed for at least 21 deaths.

Warmer-than-normal weather was on the way, but that offered little comfort to vulnerable populations such as the homeless and elderly enduring cold that caused frostbite in minutes and made being outside potentially deadly.

Officials across multiple states linked numerous deaths to the frigid air. The death toll rose from a previous 12 after at least nine more people in Chicago were reported to have died from cold-related injuries, according to Stathis Poulakidas, a doctor at the city's John H Stroger Jr Hospital.

Poulakidas, a trauma specialist, said the hospital had seen about 25 frostbite victims this week. He said the most severe cases risked having fingers and toes amputated.

Among those believed to have died from the cold was University of Iowa student Gerard Belz. The 18-year-old was found unresponsive on campus early Wednesday morning just a short walk from his dorm, according to university officials. Police told a local television station they believed the cold played a factor in his death. The wind chill at the time officers found Belz was -46 degrees Celsius, according to the National Weather Service.

Homeless and displaced people were particularly at risk, with Chicago and other cities setting up warming shelters. But many toughed it out in camps or vacant buildings. A 60-year-old woman found dead in an abandoned house in Lorain, Ohio, was believed to have died of hypothermia, Lorain County Coroner Stephen Evans said.

"There’s just no way if you’re not near a heat source that you can survive for very long out in weather like this," Evans told the Chronicle-Telegram newspaper.

15 DEGREES CELSIUS BY SATURDAY

It has been more than 20 years since a similar blast of frigid air covered a swath of the US Midwest and Northeast, according to the National Weather Service.

The bitter cold was caused by the mass of air known as the polar vortex drifting south from its usual position over the North Pole.

Homes and businesses used record amounts of natural gas to fight the cold, according to financial data provider Refinitiv. Utilities appealed to consumers to conserve energy to avoid power outages.

In Detroit, General Motors suspended operations at 11 Michigan plants to cut natural gas consumption. Fiat Chrysler Automobiles NV canceled a shift on Thursday at two of its plants.

Snow and ice created treacherous travel conditions, with 26 road collisions reported within two hours on Thursday in eastern Iowa's Johnson County, emergency communications center chief Tom Jones told the Iowa City Press-Citizen.

For the second day in a row, the intense cold and windy conditions forced US airlines to cancel more than 2,000 flights. Chicago was hardest hit, with O’Hare International Airport experiencing over 700 cancellations, according to the FlightAware tracking site.

Heavy snow hitting Chicago off the Great Lakes was set to begin winding down on Thursday night, the weather service said.

More than 30 record lows were shattered across the Midwest. Cotton, Minnesota, had the lowest national temperature recorded early on Thursday at minus -48 degrees Celsius, before the weather warmed up, the weather service reported.

Read more at https://www.channelnewsasia.com/news/world/more-than-20-dead-in-us-polar-vortex-frostbite-amputations-11194248

The Polar Vortex

Source: National Geographic

BY SARAH GIBBENS 30 JANUARY 2019

HOW THE POLAR VORTEX CREATED RECORD SUBZERO TEMPERATURES IN THE MIDWEST

Some states are seeing temperatures colder than the Arctic.

WHILE AUSTRALIANS BRACE THE HEATwaves of this year’s summer, there is no doubt that reading the winter forecasts in the United States sends a chill down our spine

In some regions of the United States, temperatures are dropping below freezing, and some portions of the Midwest are experiencing temperatures below 40 degrees Celcius and a mind-blowing wind chill of 59 degrees below zero thanks to the polar vortex. Accuweather predicts the Midwestern states will experience the extreme temperatures until later this week and cautions against stepping outside with any exposed skin. In these record-shattering temperatures, frostbite can occur after only a few minutes.

A BLAST OF ARCTIC AIR

What is the polar vortex, the doomsday-sounding weather pattern blamed for these frigid conditions?

The term refers to a swirling mass of Arctic air that hovers around the north pole all year. Its swirling eddies spin counterclockwise, and during winter months in the Northern Hemisphere, these eddies grow longer and dip farther south.

When the vortex grows, these cold swirls of air are transported south by the polar jet stream (also called the polar front). Moving from west to east, the polar jet stream hovers farther north in the summer and farther south in the winter, altered by changing seasonal sunlight. Along with its subtropical jet stream counterpart in the south, these two fronts play a determining role in seasonal weather changes.

Intermittent blasts of cold polar vortex air happen when the vortex becomes less stable, circulating in waves rather than a tight circle. According to the National Oceanic and Atmospheric Administration, denser cold air in the north and warm air currents moving south can all cause the vortex to become unstable. The more unstable the vortex becomes, the more likely it is that parts of North America, Europe, and Asia feel stray blasts of Arctic weather.

WILL CLIMATE CHANGE MAKE THE VORTEX MORE UNSTABLE?

Scientists are only recently beginning to understand how a climate changed by warming temperatures may lead to colder winters.

One study published last March in the journal Nature Communications found a link between warmer Arctic air and colder US winters, particularly in the northeastern part of the country.

WHAT IS THE POLAR VORTEX?

In a press release about the research, study author Jennifer Francis said, “Warm temperatures in the Arctic cause the jet stream to take these wild swings, and when it swings farther south, that causes cold air to reach farther south. These swings tend to hang around for a while, so the weather we have in the eastern United States, whether it’s cold or warm, tends to stay with us longer.”

One theory for why this might occur focuses on the stability of jet streams. These westerly winds are propelled by the difference between cold air in the north and warm air in the tropics. Without this strong difference, jet streams could become weaker, concluded a paper published last October.

Though global temperatures are rising, climate change could lead to more erratic, extreme weather conditions. In parts of the Midwest and Northeast experiencing these temperature drops, the risk of hypothermia makes an unstable vortex potentially deadly.