What is a Polar Vortex?


As the coldest air in 20 years surges into major population centers in United States, many are raising eyebrows over its rare cause: the positioning of the polar vortex.

A polar vortex is a large pocket of very cold air, typically the coldest air in the Northern hemisphere, which sits over the polar region during the winter season.

The frigid air found its way into the United States when the polar vortex was pushed South, reaching southern Canada and the northern Plains, Midwest and northeastern portions of the United States.

“This is why we’ve had such extreme cold,” Expert Meteorologist Brett Anderson said.


What Caused the Polar Vortex to Move?


“The polar vortex moves around at times during the course of the winter, but rarely do you see it get pushed this far south,” Anderson said.

A large, powerful high pressure system originating in the Eastern Pacific is stretching to the North Pole, shoving the vortex farther south than is typical, allowing it to settle in Canada and the U.S.

“These high pressure systems can reach Alaska, but it is not typical to stretch all the way to the North Pole,” Anderson said.

The vortex is threatening temperatures as low as minus 30 degrees Fahrenheit in the Plains and in the negative 20s and negative teens farther into the Midwest.

“The high pressure system, paired with the extensive snow cover over southern Canada and the northern United Stated, is allowing the air to stay very cold, according to Anderson.

According to the National Weather Service, the Upper Midwest, where some of the lowest temperatures are occurring, is currently more than 98 percent snow-covered.

The Upper Great Lakes region is 100 percent snow-covered, and the Midwest is more than 76 percent covered.


So, When Will the Cold Air Stop?


When the strong air from the Eastern Pacific weakens and falls apart, the polar vortex will retreat and go back into place near the North Pole.

Until then, temperatures across the northern Plains and Midwest will continue to be life-threateningly cold, shattering some all-time low records highs.

Greenland’s snow hides 100 billion tons of water

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    A drill rig was used to extract old snow (firn) cores from within the Greenland snow aquifer. (EVAN BURGESS)

Big surprises still hide beneath the frozen surface of snowy Greenland. Despite decades of poking and prodding by scientists, only now has the massive ice island revealed a hidden aquifer.

In southeast Greenland, more than 100 billion tons of liquid water soaks a slushy snow layer buried anywhere from 15 to 160 feet below the surface. This snow aquifer covers more than 27,000 square miles an area bigger than West Virginia researchers reported Sunday in the journal Nature Geoscience.

“We thought we had an understanding of how things work in Greenland, but here is this entire storage system of water we didn’t realize was there,” said Richard Forster, lead study author and a glaciologist at the University of Utah.

The discovery will help scientists better understand the fate of Greenland’s annual surface melt, which contributes to sea level rise. When the summer sun warms the Arctic island, a giant water world of stunning blue lakes and streams appears atop the ice. Tracking this surface runoff helps scientists account for ice lost to melting each year. Until now, researchers thought most of this water went to the ocean or refroze on the ice. Now they’ve found a new hiding place.

‘The existence of this rather flavorless natural snow cone has many implications for the future of the ice sheet.’

– Richard Alley, a glaciologist at Pennsylvania State University

“This throws an additional complexity into the system,” Forster told LiveScience.

There is enough water in the snow aquifer to raise global sea level by 0.015 inches, according to a separate study by the same team published Nov. 30 in the journal Geophysical Research Letters (GRL). Every year, Greenland adds 0.03 inches of water to global sea level rise from melting snow and ice, Forster said. [Top 10 Surprising Results of Global Warming]

Where water flows
No one yet knows how old the water in the aquifer is, and whether it stays trapped in the snow or reaches the ocean in slow streams or catastrophic floods. However, the top of the water table rose after Greenland’s huge surface melt in 2012, the researchers report in their GRL study.

The group will return to southeast Greenland in the coming years to answer these and other questions, Forster said. “Just seeing how old it is would answer a lot of questions,” he said.

The final destination of Greenland’s melt water is also key to understanding how the ice sheet ebbs and flows, because water under the ice sheet lubricates flowing glaciers. Researchers know some melt water goes to the bottom of the ice, trickling through cracks and racing through vertical pipes called moulins. Some of the water also simply refreezes on the surface when winter comes. Liquid water sitting in buried snow layers can also slowly warm and melt the ice sheet.

“The existence of this rather flavorless natural snow cone has many implications for the future of the ice sheet, some that may make the ice go away faster and others that help keep the ice a little longer,” said Richard Alley, a glaciologist at Pennsylvania State University, who was not involved in the study. “We would like to understand these implications better so we can help reduce the uncertainties about future changes.”

Soppy surprise
Forster and his colleagues discovered the aquifer in 2011, when a drill punched into sopping wet snow, as mushy as a summer snow cone treat or a Slurpee. (This was a year before the big surface melt of 2012.) “Water was pouring out of the core,” Forster said not what one wants to find when all the electronics are mounted outside the drill. A video of the event reveals both excitement and a few choice words among the scientists. [Watch: Discover Greenland’s Hidden Aquifer]

The water was stored in hard, compacted snow called firn the remains of the previous year’s snowfall. Forster thinks the aquifer went undiscovered because so much snow falls in this corner of Greenland.

In Southeast Greenland, frequent storms crash into tall mountains, dumping more winter snow there than anywhere else on the icy island. The thick, insulating snow blanket keeps the watery firn liquid during the freezing winter, like a down coverlet, Forster said.

Many drillers have skipped over this part of Greenland because the snow layers are so thick, Forster said, and most people who are drilling cylinders of ice from the ice sheet are looking to see the layers compacted over hundreds and thousands of years. “People who extract ice cores don’t want to go through high accumulation layers,” he said. But Forster’s team was interested in the past 10 years of snowfall, so the southeast was a good research spot, he said.

Ground-penetrating radar, towed by snowmobile, helped the researchers locate more water nearby, which the group confirmed by drilling in 2011 and 2013. When the researchers returned home, they searched airborne radar data from NASA’s Operation IceBridge and discovered the true extent of the buried snowaquifer, all in areas with heavy snowfall. Most of the water is in the southeast, but a few pockets appeared in the south and southwest, Forster said. “It all corresponds to these areas of high snow accumulation,” he said.

Greenland’s future
Researchers estimate Greenland has lost more than 200 million tons of ice and snow each year since 2003. The ice sheet will completely disappear when the planet’s average temperature rises by 2 to 7.2 degrees Fahrenheit above preindustrial temperatures, as predicted by the latest report from the Intergovernmental Panel on Climate Change, released in September.

Earth’s surface temperatures are already up 1.3 F from preindustrial temperatures, with average temperatures rising faster in Greenland.

“This doesn’t change our knowledge that too much carbon dioxide in the air will melt Greenland’s ice, but it will help us make better estimates of how much and how fast,” Alley said.

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Sparkling discovery: Antarctica may contain diamonds

  • antarctica-kimberlite

    iew looking southeast from the locality of the kimberlite samples on the slopes of Mt Meredith, across the Lambert Glacier, towards the Fisher Massif, northern Prince Charles Mountains, Antarctica. (DR GEOFF NICHOLS)

Antarctica might have a new kind of ice diamonds might exist there, a new study finds,

The finding, detailed online Dec. 17 in the journal Nature Communications, suggests the gems could be found on every continent, researchers say.

Diamonds form under the immense heat and pressure found nearly 100 miles below Earth’s surface, in the planet’s mantle layer, which is sandwiched between the outer crust and the core. Powerful volcanic eruptions bring these precious stones to Earth’s surface, where they are embedded in blue-tinged rocks known as kimberlites.

Kimberlites can range from 10,000 to 2.1 billion years in age, and can have the deepest sources of any rocks on Earth’s surface.

“Kimberlites in general inform us about conditions in the Earth’s interior,” said study lead author Gregory Yaxley, a geologist at Australian National University in Canberra. “Their geochemistry holds clues about the nature of the source rocks at these extreme depths.”

Until now, kimberlites were found on every continent except Antarctica. Now, scientists have discovered these rocks on the southernmost continent.

Kimberlites on every continent
Researchers analyzed geological samples from boulders on the southeastern slopes of Mount Meredith, part of the vast Prince Charles mountain range in East Antarctica. The scientists found three kimberlite samples that were about 120 million years old; they formed around the time when the area that is now India was drifting away from the combined landmass of Australia and Antarctica. [Antarctica: Solving Geologic Mysteries (Video)]

The kimberlites lie near the margins of the Lambert rift, an enormous, transcontinental rift that crosses much of Antarctica.

“It is likely that this rift was critical to the formation of the kimberlite, as it may have been reactivated during separation of Australia and Antarctica from India,” Yaxley told LiveScience’s OurAmazingPlanet in an email. The presence of the kimberlite may, therefore, be “a direct manifestation of large, continent-scale tectonics.”

The age of the Antarctic kimberlites and their chemical, mineral and physical features suggest they are part of a huge Cretaceous kimberlite province. This vast region is responsible for many of the world’s diamonds, and is now apparently spread across most of the continents that were once part of the supercontinent Gondwana, Yaxley said.

No Antarctic diamond mines
Only about 1 to 2 percent of kimberlites contain valuable grades of diamond, Yaxley cautioned, and of these, most are “much, much less than 1 carat of diamond per ton of kimberlite,” Yaxley said.

Establishing the viability of any clump of kimberlite as a potential diamond mine requires processing several tons of kimberlite to establish its grade, “and this is clearly unviable in the Antarctic environment,” he wrote. “Additionally, mining activity is prohibited in Antarctica under the Madrid Protocol, to which 50 nations are signatories. So, this discovery will not lead to a diamond-mining industry in the southern continent, and this is how it should be.”

Incidentally, although diamonds are often thought of as nature’s hardest material, it turns out two other rare natural substances are harder wurtzite boron nitride, which is formed during intense volcanic eruptions, and lonsdaleite, which is sometimes created when meteorites hit Earth.

Scientist finds 1959 message in bottle showing the extent of glacial melt in remote Canada

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    Climate clues: A message in a bottle left behind by a geologist in 1959 has revealed the pace of glacial retreat in remote Canada. (REUTERS)

A 54-year old message in a bottle tucked under some rocks is helping scientists study just how much a remote glacier has melted due to climate change. Canadian biologist Warwick Vincent discovered the message while on a research trip to remote Ward Hunt Island, an Arctic spot where the average temperature is -18C, reports The Chronicle Herald.

Inside the bottle was a 1959 letter from American geologist Paul Walker, recording the measurements of the glacier and asking whoever found the note to re-measure the distance and send him the information.

Mr Vincent says he instantly recognized the name of Walker, a famed geologist who died in his 20s after a medical emergency at the remote location in the same year the letter was written.

He said Walker and his colleague Albert Crary showed amazing foresight to leave the letter as a “message to the future”.

“Because in the 50s it was unthinkable this would melt”, said Mr Vincent.

“This is the most remote part of North America, and the coldest coastal zone. This also makes the evidence of substantial glacial retreat of great interest,” he told Grind TV. The 1.2-meter gap between the cairn and glacier in 1959 has today widened to 101.5 meters as the glacier shrunk.

It is extremely rare to have glacial comparisons in such a remote location, and the information is valuable to scientists, Mr Vincent told The Chronicle Herald.

“The changes are extraordinary, particularly in the last 10 years, and especially in the last years.”

And it seems the message may also reach future scientists.

After taking a photo of the letter, Mr Vincent left the bottle and message behind – adding his own note asking the next person who stumbles across it to remeasure the glacier and get in touch.

Banana-geddon: World’s bananas under threat from bugs and spreading fungus

  • Bananas

    Banana fungus threaten the global supply of one of America’s favorite snack. (ISTOCK)

One country has already declared it a national emergency and alarm bells are ringing for banana lovers.

But banana-geddon is very real and fruit fans everywhere are fearing for the future supplies of the popular global snack.

Already under massive threat due to plagues of bugs, scientists now fear a fungal infection could be making its way around the world and into banana plantations.

Fears are also growing that the Foc-TR4 strain could wipe out Cavendish cultivar banana exports across the whole of Latin American and the Caribbean, which accounts for more than 80 per cent of the world’s supply.

According to scientific journal Nature , things don’t look healthy for the world’s bananas and countries such as Costa Rica, a major exporter of the iconic fruit, have every right to be alarmed.

Previously, the disease, caused by the fungus Fusarium oxysporum f. sp.cubense (Foc), was limited to parts of parts of Asia and one region in Australia but has now been found as far away as Jordan and Mozambique.

Fusarium researcher at Wageningen University and Research Centre in the Netherlands and report co-author Gert Kema said the world needed to sit up and take notice of the potential crisis.

“I’m incredibly concerned,” he said. “I will not be surprised if it pops up in Latin America in the near future.”

According to Nature, a strain of Foc wiped out the Gros Michel cultivar – the main exported banana variety until the 1950s.

Gros Michel plants were then replaced with the Cavendish variety, which is resistant to that Foc strain, but susceptible to the new Foc Tropical Race 4 (Foc-TR4) strain.

Costa Rica is so concerned it has declared a state of emergency over its crops, with its half-a-billion-dollar export industry already been hit by two separate bug and insect plagues, The Independent reported.

The country’s agriculture ministry’s State Phytosanitary Services (SFE) director Magda Gonzalez said insect plagues made it difficult for the country to meet its export deals.

But while banana producers around the world are worried for their future, the good news is Australia’s isolation and strict quarantine standards mean our growers are in a better position.

This is obviously good news for Aussie banana fans.

But University of Queensland Associate Professor Elizabeth Aitken warned Australia couldn’t afford to be lax with its strict standards, with growing methods leaving the fruit susceptible to disease.

Associate prof Aitken said the FOC-TR4 had been found in a small region in the Northern Territory but appeared to be contained under control.

However, she warned it could get out of hand if we are not careful.

“If people are lax with things like quarantine it could be a disaster, especially for north Queensland,” she said.

Associate Prof Aitken said bananas were easily susceptible to disease and that the spread of the Foc-TR4 would be disastrous for the world’s banana producers.

Gadget garbage: UN study predicts increase in electrical waste by a third by 2017

How Green

Associated Press
  • Discarded television sets pile up in a scrap yard in China

    Aug. 26, 2013: Discarded television sets pile up in a scrap yard awaiting recycling in Zhuzhou city in south China’s Hunan province. China’s recycling industry has boomed over the past 20 years. Its manufacturers needed the metal, paper and plastic and Beijing was willing to tolerate the environmental cost. (AP PHOTO)

BERLIN –  The mountain of refrigerators, cellphones, TV sets and other electrical waste disposed of annually worldwide is forecast to grow by a third by 2017, according to a U.N. study released Sunday.

E-waste — defined as anything with a battery or a cord — can pose a big problem because it often contains substances that are harmful to humans and the environment if not properly treated. On the other hand, some of it can be profitably recycled.

A U.N. think tank dedicated to the issue estimates that the amount of e-waste will rise from almost 48.9 million metric tons (53.9 million tons in 2012 to 65.4 million metric tons (72.09 million tons) in 2017. That’s nearly 200 times the weight of the Empire State Building.

The U.S. dumped the most last year, generating 9.4 million metric tons of e-waste, followed by China with 7.3 million metric tons.

Per capita the U.S. was even further ahead, with almost 66 pounds of high-tech trash for China’s 12 pounds. The global average is 15 pounds per person.

But China is catching up, evidenced by the fact that it had the highest volume of electrical goods put on the market last year with 11.1 million metric tons. The U.S. had about 10 million metric tons.

Taken together, developing and emerging countries already produce as much e-waste as the developed world, said Ruediger Kuehr, who heads the StEP secretariat, based at the United Nations University in Bonn, Germany.

“There is a hunger of humankind for technology that makes our lives easier,” Kuehr told The Associated Press. “It’s not only the communication technologies but also medical devices, washing machines and e-toys that are very popular around Christmas time.”

The report, which based its findings on estimates of how long such products last, and hard data on discarded products in several country, is the first time that globally comparable data on e-waste have been publicly released, he said.

It was published in tandem with a study by the Massachusetts Institute of Technology and the U.S. National Center for Electronics Recycling tracking the flow of such scrap across borders.

The study, which excluded white goods because there are established recycling systems for those in the United States, found that mobile phones are the most common item of e-waste in the U.S.

About 120 million phones were discarded in 2010. Many of those ended up going to Hong Kong, Latin America and the Caribbean.

The authors of the study called for better monitoring of e-waste exports, saying lack of consistent categories makes it hard to formulate effective rules for the treatment of electrical junk.

Heavy fog enshrouds london

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    A thick fog blankets London’s Canary Wharf business district on Dec. 10, 2013. (METROPOLITAN POLICE | @MPSINTHESKY)

An impenetrable fog rolled into London Wednesday morning, which caused some travel woes, and also produced rare views of the city’s skyline from above, with only the tallest buildings poking above the mist.

While many planes at London’s major airports were grounded, a team of officers with the city’s Metropolitan Police Service (MPS) flew above the fog in a helicopter. One of the members of this Air Support Unit snapped this amazing photo with an iPhone and posted it to Twitter.

Fog collects under very humid conditions when water vapor condenses into very small droplets of water, which are suspended in air.

A type of fog known as radiation fog most commonly forms in the winter, under calm conditions and clear skies, when the sun’s absence overnight cools air close to the ground. Radiation fogs often dissipate in the morning, when the sun comes out again and warms the ground, according to the Met Office, the United Kingdom’s national weather service. [See Photos of the Weirdest Clouds]

London’s fog enshrouded the city overnight Wednesday and lasted through mid-morning Thursday. According toAccuWeather.com, weather conditions in London late Tuesday evening were ripe for fog formation.

“Clear skies and calm winds are the main causes of fog,” said AccuWeather meteorologist Dan DePodwin, adding that winds out of the southeast on Tuesday had helped bring moisture to the area.

The Met Office had issued warnings that visibility would be lower than 165 feet, and the fog, which has since lifted, caused many cancelations and delays at Heathrow andLondonCity airports, The Guardian reported.

“Fog is a challenging condition to fly around, but once above it we were able to carry out our normal taskings,” Captain John Roberts (call sign India 99), who was piloting the MPS helicopter, said in a statement.

Though London police officials said their @MPSintheSkyTwitter account was initially set up to field complaints about helicopter noise, they’ve seized the opportunity to share photos from their unique perspective of the city and its landmarks.

“We’re proud to be able to provide great images of our iconic city,” Roberts said in a statement.

London may be better known for its history of smog than fog. What is sometimes referred to as the great fog of 1952 in London was actually the great smog, as the thick veil covering the city was the result of smoke pouring from chimneys during a cold spell that December. Typically, that smoke would rise and disperse, but a weird weather pattern called an anticyclone was hanging over the region, according to the Met Office. These conditions, combined with calm winds, caused what’s known as a temperature inversion, trapping cool air close to the ground underneath warmer air. Chimney smoke and other particles got trapped in the resulting fog, creating a serious bout of air pollution. About 4,000 people died due to the great fog, according to the Met Office.

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Canada makes North Pole claim

Associated Press
  • Canada Arctic Soverei.jpg

    In this March 31, 2007 photo, Ranger Joe Amarualik, from Iqaluit, Nunavut, drives his snowmobile on the ice during a Canadian Ranger sovereignty patrol near Eureka, on Ellesmere Island, Nunavut. Canada plans to make a claim to the North Pole in an effort to assert its sovereignty in the resource-rich Arctic, the country’s foreign affairs minister said Monday, Dec. 9, 2013. (AP)

Canada plans to make a claim to the North Pole in an effort to assert its sovereignty in the resource-rich Arctic, the country’s foreign affairs minister said Monday.

John Baird said the government has asked scientists to work on a future submission to the United Nations claiming that the outer limits of the country’s continental shelf include the pole, which so far has been claimed by no one.

Canada last week applied to extend its seabed claims in the Atlantic Ocean, including some preliminary Arctic claims, but it wants more time to prepare a claim that would include the pole.

‘We are determined to ensure that all Canadians benefit from the tremendous resources that are to be found in Canada’s far north.’

– Canada’s foreign affairs minister John Baird

Asserting Canada’s rights in the Arctic has been a popular domestic issue for Prime Minister Stephen Harper, though at least one expert on the issue described the planned claim as a long shot.

“We are determined to ensure that all Canadians benefit from the tremendous resources that are to be found in Canada’s far north,” Baird said.

Countries including the U.S. and Russia are increasingly looking to the Arctic as a source of natural resources and shipping lanes. The U.S. Geological Survey says the region contains 30 percent of the world’s undiscovered natural gas and 15 percent of oil. If Canada’s claim is accepted by the U.N. commission, it would dramatically grow its share.

Countries must submit proposals to the U.N. Commission on the Limits of the Continental Shelf to request an extension of their nautical borders. Currently, under international law, Canada, Denmark, Norway, Russia and the U.S. —the five countries with territories near the Arctic Circle_are allotted 200 nautical miles from their northern coasts.

Under the U.N. Convention on the Law of the Sea, exclusive claims can be vastly expanded for Arctic nations that prove that their part of the continental shelf extends beyond that zone.

Baird said Canada’s submission last week set out the potential outer limits of the country’s continental shelf in the Atlantic — a claim of about 1.2 million square kilometers. He said that’s roughly the size of Alberta and Saskatchewan combined.

Canada’s follow-up submission will include a claim to the Lomonosov Ridge, an undersea mountain range between Ellesmere Island, Canada’s most northern land mass, and Russia’s east Siberian coast. That claim would extend Canada’s claim 200 nautical miles beyond the North Pole.

The submission that Canada filed with the U.N. is essentially a series of undersea co-ordinates that map what the government claims is the country’s extended continental shelf.

Baird said it’s a mammoth task, and the government needs more time to complete the mapping in the Arctic and get its U.N. submission right.

“That’s why we have asked our officials and scientists to do additional and necessary work to ensure that a submission for the full extent of the Continental Shelf in the Arctic includes Canada’s claim to the North Pole,” he said.

The U.N. submission is also political, said Michael Byers, an expert on Arctic and international law at the University of British Columbia.

“(Harper) does not want to be the prime minister seen publicly as having surrendered the North Pole, even if the scientific facts don’t support a Canadian claim,” Byers said. “What he’s essentially doing here is holding this place, standing up for Canadian sovereignty, while in private he knows full well that position is untenable.”

The U.N. submissions do not lead to a binding decision, but lay the groundwork for future country-to-country negotiations over competing territorial claims in the Arctic that could take years to resolve. Just checking the science on a claim likely will take five years, said Rob Huebert, an Arctic expert at the University of Calgary.

Byers said there isn’t any particular rush for Canada to stake its claim for the North Pole, pointing out that such claims cover some of the most remote and harshest places on the planet, and commercial exploitation of resources is a long way off.

“We’re talking about the center of a large, inhospitable ocean that is in total darkness for three months each year, thousands of miles from any port,” he said. “The water in the North Pole is 12,000 feet (3,650 meters) deep and will always be covered by sea ice in the winter. It’s not a place where anyone is going to be drilling for oil and gas.

“So it’s not about economic stakes, it’s about domestic politics.”

Ask a science teacher: Why is snow white, and where does its color go when the snow melts?

  • science-teacher-snow-works.jpg

Snow is a bunch of ice crystals stuck together. It’s a very complex arrangement. To understand why snow is white, we must be familiar with what happens to light when it strikes any material. The color of anything, including snow, depends on how light interacts with it.

Visible light consists of a rainbow of colors, the ROY G BIV colors of red, orange, yellow, green, blue, indigo, and violet that were assigned by Isaac Newton. When photons of light strike an object, they may bounce back (reflection), bounce to the sides (scattering), pass right through (transmission), or give up their energy (absorption). Grass is green because it reflects the green light to our eyes and absorbs all the other colors. Red apples reflect red light to our eyes and absorb the wavelengths of all the other colors.

When light goes into snow, it hits all those ice crystals and air pockets and bounces around, and then some of the light comes back out. Snow reflects all the colors; no it doesn’t absorb, transmit, or scatter any single color or wavelength more than any other. The “color” of all the light wavelengths combined equally is white. So all the colors coming out are the same colors that go in, combining to make white light.

A few years ago, I visited the famous Mendenhall Glacier in Juneau, Alaska. The glacial ice looked bluish. Ice is just very compact snow, without a lot of light-scattering bubbles. Light can penetrate much deeper into ice than into snow. The deeper the light goes, the more the longer wavelengths, toward the red end of the spectrum, get scattered out, and eventually the reds dissipate, leaving only blue colors to be reflected back to us. So the ice takes on a beautiful, eerie blue tone.

The record snowfall for any one year in the United States is 1,140 inches (95 feet) at Mount Baker Ski Area in northwestern Washington, during the 1998–1999 snow season.

Snow is beautiful. It coats everything in a pure white blanket. It helps farmers and is good for the land, because it has a ton of air pockets. Even though the snow itself is cold, the air that they hold in insulates the ground, protecting seedlings and preventing the frost from going too deep. Snow that falls in the mountains later melts and helps fill the depleted reservoirs of the American West.

You may have noticed how quiet it is outside after a fresh snowfall. In addition to making snow fluffy those air pockets absorb sound, just like the ceiling tile in my classroom. After a few days, sound travel returns to its normal pattern. Many of the fluffed-up ice crystals melt and compact somewhat, so the tiny pockets that absorbed sound are gone.

When I was a kid on the farm, my dad planted fields of oats in April. One year the oats were up about three inches when we got one of those late-spring snowstorms with four or five inches of snow. I thought all the oats would be dead. Strangely, my dad didn’t seem to be concerned. Turned out those were some of the best oats we ever had. I remember him mentioning something about the snow adding nitrogen to the soil, which makes sense because moisture helps plant seedlings fix nitrogen in the soil.

From the book, “Ask a Science Teacher: 250 Answers to Questions You’ve Always Had About How Everyday Stuff Really Works“; Copyright © Larry Scheckel, 2013. Available December 17 wherever books are sold.

Rare weather event fills Grand Canyon with fog

  • grand-canyon-fog-1

    The Grand Canyon, filled with fog, in a rare weather event called a temperature inversion. (NATIONAL PARK SERVICE PHOTO BY ERIN WHITTAKER)

Usually the Grand Canyon offers stunning views stretching for miles, deep into valleys etched by the Colorado River. But that vista has changed over the past few days, as a rare weather event has filled the canyon with fog, offering an even more stunning view than is typical.

The weather event is known as a temperature inversion, and it only happens every few years, according to the National Park Service, who wrote about the event and posted photos of it on its Facebook page.

Temperature inversions typically happen in the winter when there are long nights, and as the name implies, an inversion takes place when a layer of cool air gets trapped underneath warmer air, according to the National Weather Service (NWS). This is the reverse of the usual pattern, with temperature generally decreasing with increasing altitude. [See Amazing Photos of the Grand Canyon]

“Once the sun goes down, the ground loses heat very quickly, and this cools the air that is in contact with the ground,” the NWS explained. “However, since air is a very poor conductor of heat, the air just above the surface remains warm. Conditions that favor the development of a strong surface inversion are calm winds, clear skies, and long nights,” which is exactly what’s taking place in the Grand Canyon now, according to weather reports.

“Calm winds prevent warmer air above the surface from mixing down to the ground, and clear skies increase the rate of cooling at the Earth’s surface,” the NWS continued. “Long nights allow for the cooling of the ground to continue over a longer period of time, resulting in a greater temperature decrease at the surface.”

If moisture is trapped in this layer, it can form fog, as happened in this case. So far the inversion has taken place on two of the past few days in the Grand Canyon, which rarely happens, especially on days with blue, clear skies, the NPS wrote.

The Grand Canyon, which wends 277 miles along a sinuous path, became a national park in 1919; at that time some 44,173 visitors enjoyed the billions of years of history tucked into its colorful rocks. That’s compared with the nearly 5 million visitors to the park today, according to NPS.

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.