Extreme Temperatures
"The virus likes cold, wet and cloudy days," said Rodney Baker, a swine veterinarian at Iowa State University at Ames, Iowa, the top pork producing state in the United States.
At this time of year the virus gets frozen on clothes and shoes, making it easy to track around and spread, Baker added.
Porcine Epidemic Diarrhea virus (PEDv), which causes diarrhea, vomiting and severe dehydration in hogs, has spread quickly across the U.S. hog belt since its discovery in the United States in April 2013.
California and Wyoming are the latest states to report confirmed cases of the deadly pig virus, bringing the number of states affected to 22, the U.S. Department of Agriculture said on Thursday.
The number of new cases increased by 134 for the week of December 29, bringing total reported cases to 2,084, according to the USDA's National Animal Health Laboratory Network (NAHLN)
The polar vortex which has gripped North America in sub-zero temperatures has brought with it a natural phenomenon on the shores of Lake Michigan.
Huge, basketball-sized balls of ice have been washing up by the lakeside town of Glen Arbor in Michigan.
Meteorologist Joe Charlevoix explains that they are formed when "the water temperature on the Lake Michigan is just a little bit below freezing, so you get a small piece of ice that forms in the water and as waves move back and forth it adds additional water and freezes in layers.
"It gets bigger and bigger, and eventually you get big balls of ice, that are pushed to the shore by the wind."
Locals call them "ice balls" or "ice boulders" and they are a regular feature of Winter in the Great Lakes.

A wrecked semi truck sits in a ditch in Illinois as sub-zero temperatures hit driving conditions.
- Montana recording a record-making wind chill of -52C (-61F)
- Live blog: life-threatening cold hits North America
Millions of Americans from Montana down to as far south as Alabama are being warned that their lives are at risk if they venture out for any length of time into brutally cold conditions that are driving temperatures to their lowest in 20 years.
Severe weather warnings from the National Oceanic and Atmospheric Administration for Minnesota and Wisconsin said that wind chills caused by gusts of up to 30 mph were causing temperatures to plummet to between -37C (-35F) and -46C (-50F). "Exposed flesh will freeze and cause frost bite in only five minutes," the warning observed, adding that such dangerous conditions were likely to last until at least Tuesday afternoon.
Twenty six states continue to be under federal warnings for severe wind chills as bitterly cold air is swept down from the Arctic, with Montana recording a wind chill of -52C (-61F). The severe weather has already caused havoc in the Northern Plains and is expected to reach the north-east on Tuesday, extending disruption to airports and travellers. More than 3,000 flights were cancelled on Monday and Chicago's O'Hare International airport has been particularly badly affected.

Ice builds up along Lake Michigan at North Avenue Beach as temperatures dipped well below zero on Jan. 6, 2014 in Chicago, Illinois.
In his executive order on climate change, Obama warned that too much rain - and not enough rain - also dictated that executive action against climate fluctuations:
"The impacts of climate change -- including an increase in prolonged periods of excessively high temperatures, more heavy downpours, an increase in wildfires, more severe droughts, permafrost thawing, ocean acidification, and sea-level rise -- are already affecting communities, natural resources, ecosystems, economies, and public health across the Nation. These impacts are often most significant for communities that already face economic or health-related challenges, and for species and habitats that are already facing other pressures."

Weather Channel producer Shawn Reynolds tweeted this incredible photo taken by pilot Hank Cain of a tundra-like Chicago, from above.
Thanks for the memories, polar vortex.
Florida, a state that normally basks in its reputation as a warm winter escape, experienced unusually low temperatures. In the midwest, northeast and eastern Canada, it was dangerous to venture outside. At some point on Tuesday, at least one location in each of the 50 US states recorded temperatures below freezing, with the highest point on Hawaii, Mauna Kea, recording a temperature of 21F (-6C).
The so-called polar vortex that funnelled an Arctic low pressure system into the upper US this week swung south and east on Tuesday. Polar conditions settled over two-thirds of the US.
It was colder in the southern state of Georgia than Alaska as Atlanta plunged to 6F (-14C) - the lowest temperature since 1966 - while Anchorage, Alaska, recorded 27F (-3C) . Wind chills were recorded around -60F in parts of Michigan, Minnesota, Montana and New Hampshire.

Experts say you should keep a trickle of water running in extreme cold to keep pipes from freezing.
CBS 2's Dave Carlin went in search of some tips on how to protect your house for the bitter blast.
Phyllis Dalton of Levittown was standing right under the spot Monday where several years ago, a water pipe snapped during a cold snap.
She promised herself it would never happen again, and started winterizing.
"You pay attention and you do those little things," Levittown said.
Levittown learned just like people need layers of clothing in the extreme cold, houses also need layers of protection. The advice is particularly important in preventing freezing pipes.
"(There is) a valve - a shut off valve," said Brian Bruce, who operates New York American Water.

A woman sit on the floor while her flight is delayed at La Guardia airport in New York, January 6, 2014.
JetBlue halted operations at all three major New York-area airports and in Boston in an effort to catch up with dozens of weather-related delays and cancellations.
The airline announced Monday that operations stopped entirely at Newark, John F. Kennedy International and LaGuardia airports and at Boston's Logan International Airport at 5 p.m.
The plan allows 17 hours for the company to rest crew and time to service aircraft.
As CBS 2′s Tracee Carrasco reported, stranded travelers had nowhere to go and nothing to do Monday but wait and sleep in airport terminals.
JetBlue customer Julia Moron has been desperately trying to get home to Houston for days.
"I've been stuck here between JFK and now LaGuardia since Thursday," she said.
I don't care if you are rich or poor. Your skin color matters not, nor your political leanings. We all have to prepare for the obvious and the sooner you do, the quicker your life can begin some sense of normality.
Preparing for an ice age means that you will have to alter your diet to meet available foodstuffs. Planning now is the smartest decision you can make.
The sun, the life giving big ball of gas, is not acting normal. It's acting sluggish. And when it does that, we enter into periods of global cooling. These three articles tell us that the sun is at a low:
- Solar activity drops to 100-year low, puzzling scientists
- Sun Is Weakest In 200 years
- Starvation: Coming to Your Town...Soon
The problem has been defined. The solution - not that difficult! It will require work and basic knowledge, but if our ancestors could survive, so can we.
First, your diet needs to change. A meatless diet simply will not work, as the body needs cholesterol in order to make the necessary hormones like adrenaline, testosterone, and estrogen. As the mercury drops to sub-normal temperature, cholesterol will be used by the body because of increased activity to stay warm. The shiver reflex helps raise the body's temperature, the testosterone will increase body hair to help stay warm, and estrogen will help thermoregulate a woman's body.