March 31, 2010

Pigs DO fly – in a tornado simulator

Posted: 01:04 PM ET

Tornado simulators are a staple of science classes and science museums.

Want to see cyclonic action at work? Fill a two-liter bottle with water, connect it to another at its mouth, give it a swirl and watch the water power into the lower bottle . Science museums often have more elaborate forms of this showcase, creating a “tornado” out of air or water vapor at the push of a button.

Now the Weather Channel is getting into the act – virtually.

On its Into the Tornado page – meant to promote next week’s “Tornado Week,” naturally – users have the opportunity to watch a tornado do its thing. You can click on a car, a train, a pickup truck or a pig – among several choices – set the power of the tornado and then the point of view.

One thing’s for sure: It’s bad enough watching what happens to a train or car in an F5 tornado, but you definitely don’t want to be a pig. In an example, a porker gets hurled almost 400 feet in the air and ends up 167 feet from its starting point. As the accompanying text warns, “Tornadoes will rip through farms turning our porcine friends into dangerous pink missiles.” (Keep your Beavis and Butt-head jokes to yourself.)

There are no cows available, but if you’re looking for that, you can always rent “Twister” again.

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Filed under: Tornadoes • Weather

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January 26, 2009

Banana hammer cold

Posted: 11:13 AM ET

From the West, to Midwest, the Northeast to parts of the South it's cold. I mean banana hammer cold. Never seen that measurement on the thermostat? Well, you've obviously never been to Minnesota in the winter.

How cold is it? Cold enough to turn a banana into a hammer. Photo: Getty Images

Meteorologist Jonathan Yuhas from Minneapolis affiliate KARE showed CNN's Heidi Collins what last week's subzero temperatures could do to everyday items.

According to KARE, on January 15 it was negative 21 degrees Fahrenheit, factoring in the windchill. That's just 17 degrees warmer than the freezing point for liquid mercury. And one more reason I will not visit Minnesota in the winter.

Now, bubbles don't shatter and hot water doesn't turn to a frozen cloud in normal weather conditions. It has to be cold. Very cold. Cold enough to pass those items' freezing limit.

Generally defined, a freezing point is the temperature where the liquid state of a particular compound freezes to form a solid. For freshwater, this temperature is 32 degrees Fahrenheit. For a banana or other foods, it depends.

A work by Dr. Richard W. Hartel of the University of Wisconsin-Madison states that "foods are mixtures of various ingredients, some of which affect phase behavior of water.." Meaning, since foods contain sugars, salts, proteins, fats, flavors, etc., there is no one broadly defined freezing point for food. For fruits, Hartel gave a general freezing point between 30.4 – 27.1 degrees Fahrenheit.

Hartel also gave the average freezing points of some other food categories:

Vegetables: 30.6 – 26.7 F
Meat: 28.9 – 28.0 F
Egg: 31 F
Milk: 31 F

Ice, snow, banana hammers, frozen bubbles–at 21 below, they're all the same. Frozen.

According to, which is my authority on everything bubble-related, it is possible to freeze bubbles. Our iReporters also proved us that. But once the bubble freezes, it's only a matter of time before they shatter.

This is because when a bubble is blown into subzero temperatures, the warm air inside the bubble quickly contracts. The volume of air becomes lower, and the bubble crumples under its own weight.

CNN iReporters also got in on the action, freezing everything from food to flash-freezing hot water. Others are using the freezing weather to go green. iReporter Kyle Aevermann shared his use of a "natural freezer" in Chicago's subzero temperatures.

The Food and Safety Inspection Service, a branch of the USDA, recommends against doing that, however. The agency's Web site Fact Sheet states: "When it is freezing outside and there is snow on the ground, it seems like a good place to keep food until the power comes on; however, frozen food can thaw if it is exposed to the sun's rays even when the temperature is very cold. Refrigerated food may become too warm and foodborne bacteria could grow. The outside temperature could vary hour by hour and the temperature outside will not protect refrigerated and frozen food."

So besides food, what else have you found freezing point for? Wet laundry? An umbrella? We want to know. Send in your iReports. Leave a comment.

- Brandon Ancil,

Filed under: science • Weather

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November 10, 2008

Great big ozone hole this year - not as bad news as it sounds

Posted: 09:29 AM ET

The ozone hole over the Antarctic, which grows to its maximum annual size in September, peaked at the fifth-highest size ever since measurements began in 1979 this year, according to scientists at the National Oceanic and Atmospheric Administration.noaa-ozone

But experts say that the "fifth-largest" designation may not necessarily be bad news at all.  They're sticking to predictions that the ozone hole will repair itself over the rest of the 21st Century.  Colder-than-average temperatures and strong high level winds helped widen the hole this season.  Warmer weather as the Antarctic summer starts up helps close up the hole each year.

It's been nearly four decades since the first research drew links between man-made chemicals and destruction of ozone in the upper atmosphere.  Chlorofluorocarbons and freon - once widely used in air conditioners and spray cans respectively, were among the substances that broke down stratospheric ozone - the key to protecting us from harmful solar radiation.  Projections indicate that a thinning ozone layer could lead to increases in human skin cancer, eye cataracts, and other maladies.  Dutch scientist Paul Crutzen and Americans Mario Molina and Sherwood Rowland shared the 1995 Nobel Prize for Chemistry for their discoveries.

Global concern over ozone damage led to what is widely regarded as a remarkably successful international treaty.  The Montreal Protocol was ratified in 1987 and took full effect nine years later, banning most uses of ozone-destroying chemicals.

Scientists have reported a substantial reduction in the levels of ozone-destroying chemicals reaching the stratosphere.  But CFC's, freon, bromides, and other ozone-eaters are particularly long-lasting, and may take much of the rest of this century to dissipate.  "The decline of these harmful substances to their pre-ozone hole levels ... will take decades," said NOAA chemist Stephen Montzka.

Translation:   Don't lose the sunscreen.   Ozone layers have thinned planet-wide, and during the late-winter weather in either hemisphere, ozone protection reaches its lowest levels near the poles.  Less ozone in the upper atmosphere means more exposure to the ultraviolet radiation that can cause skin cancer.

NOAA's Ozone measurements page can be found here

NASA offers daily updated graphics and animations on the size of the ozone hole here.

Peter Dykstra   Executive Producer   CNN Science, Tech & Weather

Filed under: environment • meteorology • NASA • science • Weather

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November 3, 2008

The political impact of Election Day weather

Posted: 11:02 AM ET

It seems rain DOES make a difference when deciding an election.  As matter of fact it might have cost Al Gore the White House in 2000.  

Election Day weather across the U.S. looks mostly dry - a good sign for Democrats?

According to Florida State University researcher Brad Gomez (along with Thomas G. Hansford and George A. Krause), just an inch of rain can make a big difference in a tight race.  (Gomes, who recently joined the faculty at FSU, did his research while at the University of Georgia). 

The researchers studied the past 14 presidential elections using simulated weather conditions for those dates based on data from more than 22,000 weather reporting stations. They found that while 1 inch of rain drops overall voter turnout by less than 1 percent, the Democratic turnout drops by 2.5 percent.  There was significant rain in the Florida panhandle during the controversial 2000 election when George W. Bush beat Gore by just hundreds of votes in Florida to win the presidency.  If it hadn’t rained, enough additional Democrats might have voted in Florida to give Gore the White House.

Other interesting findings in the study show that younger voters are less likely to vote in bad weather while older voters are more inclined to vote rain or shine.  (Once again we need to follow the lead of our elders and vote - regardless of the weather!!!)

So where might weather play a role during Tuesday's voting?  The weather map looks pretty simple: The battleground state of North Carolina, where both the presidential race and a U.S. Senate race are competitive, will see some rain along the coast.  The rest of the eastern half of the country should be dry. Areas west of the continental divide will see some valley rain and mountain snow.

Does that mostly dry forecast bode well for Barack Obama and the Democrats this time? We'll soon find out.
–Rob Marciano, CNN Meteorologist

Filed under: Weather

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October 2, 2008

Hurricane Ike hits Chicago

Posted: 11:52 AM ET

Hurricane Ike went down in the weather annals as the third-costliest tropical cyclone in U.S. history. Weeks after Ike's landfall, a whirlwind of destruction can still be felt hundreds of miles inland, in the Great Lakes region.

Hurricane Ike
Getty Images/NASA

Heavy rains from Ike and the Pacific Tropical Storm Lowell inundated northwestern Indiana and metro Chicago. The ground was already saturated by a stalled cold front so the increased flooding caused runoffs from streams and rivers, dumping sediment into Lake Michigan and increasing E. coli levels in the water.

United States Geological Survey (USGS) scientists have been monitoring the water in Lake Michigan after Hurricane Ike, as part of an effort to improve predictions of beach water quality.

Dr. Richard Whitman, USGS expert on beach health ,says, "The local effects that Ike had on Lake Michigan's Indiana shoreline, water depth, and water quality have been profound."

Typically after a storm, bacteria levels rise along near-shore water sources, but, Ike brought with it a slew of other problems. The flooding caused by Ike loaded up Lake Michigan with contaminants that could not be diluted for an unprecedented ten days.

The unexpected flooding also made it impossible for wastewater treatment plants to properly treat the overflow of storm water coming in. Run-off from agricultural and septic tanks all increased the E. coli levels in surrounding rivers, which then fed into Lake Michigan. At one point, river water levels during the storm got so high that they actually flooded the sewage plants.

The EPA says that E. coli concentrations of 235 CFU (Colony Forming Unit) per 100 ml of water would be an acceptable risk level for freshwater sources. At the height of its contamination, E. coli levels reached an estimated high of 1,200 CFU per 100 ml of water. In other words, an average of 17 out of 1000 swimmers could expect to get a gastrointestinal illness from swimming in parts of Lake Michigan after Ike, in comparison to the usual 8 out of 1,000 people.

USGS scientists say E. coli levels are now back to normal but the sediments in the water have yet to be cleaned up. Ike proves that we live in a fluid environment and what happens to our neighbors could eventually affect us too, be it upstream or downstream.

Azadeh Ansari, CNN Sci-Tech Unit

Filed under: environment • Flooding • hurricanes • Severe weather • Uncategorized • Weather

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September 24, 2008

Southeast US still running dry

Posted: 09:25 AM ET

While we're watching the election, the hurricanes, Wall Street hitting an iceberg, and a worsening gasoline shortage here in the Southeast, this part of the country is still in crisis over another precious resource: Water.

A cove and docks on Georgia's Lake Lanier, 2003

A cove and docks on Georgia's Lake Lanier, 2003

Though it's been largely out of the news the Southeast drought continues. In fact, 35.1% of the southeastern region is in moderate drought or worse. Now to be fair, at this time last year that number was 76.7%. Plus, when talking extreme drought, only 6.9% of the region is classified as extreme, whereas that percentage was an incredible 41.7% last September.

So where is all the water if the acreage of drought is down? Many areas of the Southeast are now in what is called a hydrological drought. That is a technical term for Phase Two. In Phase One (agricultural drought), crops, grasses and other shallow rooted plants get stressed by the lack of available moisture for growth. Your grass turns brown, but the lakes are still relatively full. Now all droughts start as a deficiency of precipitation, but this Phase Two issue now affects rivers and reservoirs. Your grass is brown and your boat is aground. Some areas are in Phase Two-B….dead grass…empty lake and dry well.

Dry, weed-choked, and the docks are now dry-docks.  (Photos Wendy Green)

The same cove last month: Dry, weed-choked, and the docks are now dry-docks. (Photos Wendy Green)

And this is a multi-year drought…in Atlanta, last year brought a rainfall deficit of 18.2” and now 2008 is another 8.0” down compared to normal.

What is a little more telling is available drinking water for the cities in the area. The water supply for a major part of metro Atlanta is Lake Lanier. Currently, Lake Lanier is 16.4 feet below summer full pool. Last year it was 11.5 feet low at this time, yet the major media was all over it. Drought in 2008 seems to be “Old” news even though the reality of long term drought makes this year much more extreme.

I talked to Assistant Professor Georgina DeWeese, Ph.D. in Biogeography and Physical Geography at the University of West Georgia. She said, “People need to realize that water is a resource and not an unlimited one. Drought is going to be here a while. Get used to it and start saving water.”

So the grass is dead and you can’t launch your boat, but what about those that depend on the rain to make their livelihoods? Some farmers have lost two years of income and culled their herds….plant nurseries have filed for bankruptcy…lake front houses have no lake… but, what if Atlanta runs out of water? Can you say mass migration? How long do you think you could live without any water coming out of your tap? A week? A month? Maybe.

So not to be a fatalist…people must stop WASTING water. Can you believe in Cobb County, Georgia a person can’t power wash their house, but they CAN hire someone to do it. From the county’s website….”Pressure washing can only be performed by a licensed professional.” What? They are still using water!

Chad Myers CNN Meteorologist

Filed under: environment • meteorology • Weather

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September 6, 2008

Hanna/Ike, 11am Sunday Update

Posted: 12:22 PM ET
Here's the 11am Sunday update, based on the National Hurricane Center's forecast and info from CNN's meteorologists;
IKE:  Category Four, major storm, Max Sustained Winds 135 MPH, forward speed 13 mph.  Ike is tearing through the Turks and Caicos and extreme southern Bahamas, with some potentially catastrophic collateral damage to Haiti from heavy rain, floods, and mudslides.

Projected track of Hurricane Ike as of 11am ET Sunday, according to the National Hurricane Center.

Projected track of Hurricane Ike as of 11am ET Sunday, according to the National Hurricane Center.

The storm is now expected to track the length of Cuba, including mountainous areas, that could really deflate the storm.  But after exiting Cuba, Ike will re-intensify, and is expected to recover to Cat Three strength.  All of the forecast models are within about fifty miles of each other for Ike's path across Cuba.
The lower Florida Keys could see some impact from the storm on Tuesday, but are pretty much out of danger from a direct hit.  The forecast models are a bit scattered on an ultimate US landfall, ranging from Galveston Bay/Houston to the west and Mobile Bay to the east.  Earliest possible landfall, if the storm takes the shortest path and stays east, would be Thursday.   Friday or Saturday is more likely, but as always, this is way too far out to make more than a guess for Ike's destination, arrival time, and intensity at landfall.

Hanna is offshore, likely to impact Nova Scotia and Newfoundland today, and tracking to cross the ocean and possibly cause a bit of grief in Scotland/Northern Europe later this week, but its US impacts are done.
Josephine is off the maps completely, now a mid-Atlantic disturbance posing no threat to land.



Peter Dykstra   Esecutive Producer, CNN Science, Tech, & Weather

Filed under: environment • Flooding • hurricanes • meteorology • Oceans • Severe weather • Weather

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September 4, 2008

Tropics brace for the Ike & Hanna show

Posted: 12:42 PM ET

Position of the three tropical systems as of 11am ET Thursday, according to the National Hurricane Center

Position of the three tropical systems as of 11am ET Thursday, according to the National Hurricane Center

The good news? Josephine is well out in the mid-Atlantic, and if its track holds, it will stay there.
The wobbly path of Tropical Storm Hanna continues, and as of 11am ET Thursday, the best guess of the National Hurricane Center is that the storm will strengthen to a Category One hurricane and make landfall, perhaps near Wilmington, North Carolina, at about midnight Friday. Hanna could spread its damage all the way up the US East Coast as it tracks toward the northeast.

Hurricane Ike could be a big one. It strengthened from a Category One to Category Four storm in less than half a day yesterday, and its current track could bring it into south Florida on Tuesday as a Cat Three. Ike's entry into the Gulf of Mexico is still a strong possibility.

One reason for the projected weakening of the storm is that Hanna could steal some of Ike's thunder (and winds, and rain), according to CNN Meteorologist Rob Marciano: Tropical systems stir up deeper, colder water, and some of the ruckus that Hanna has caused. As Ike passes over that cooler surface water, it could be weakened just a bit.

Peter Dykstra Executive Producer CNN Science, Tech & Weather

Filed under: climate change • environment • hurricanes • meteorology • Oceans • Severe weather • Weather

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September 3, 2008

Watching the Arctic ice melt

Posted: 12:59 PM ET

September marks the time of year when polar ice cover is at its lowest. After last year's record low, Arctic researchers say we're in for another bad year – and what is perhaps an irreversible trend.

Polar ice cover as of yesterday. Source: Univ. of Illinois Polar Research Group

On Tuesday, scientists reported another Manhattan-Island-sized chunk broke off an Ice Shelf on Ellesmere Island in the Canadian Arctic.

a University of Illinois site allows you to bring the out-of-sight/out-of-mind Arctic to your desktop. If you want to track the day-by-day status of the Arctic ice cap, and compare it to past years, go here. The images, from the Illinois Polar Research Group, track Arctic ice coverage day by day back to 1979. See for yourself, and let us know what you think.

Also - more tomorrow on our parade of hurricanes across the Atlantic: Hanna looks to have uncertain potential for East Coast damage; Josephine hopefully will remain a mid-Atlantic storm and not reach land; but Ike could be a big one for the Gulf of Mexico.

Peter Dykstra Executive Producer CNN Science, Tech & Weather

Filed under: climate change • environment • hurricanes • meteorology • Oceans • Severe weather • Weather

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September 2, 2008

'Conga Line' of storms across the Atlantic

Posted: 01:30 PM ET

Just like the dance-hall Conga Lines of the 1950's and earlier, tropical systems are lining up across the Atlantic and headed this way. Let's take a look one-by-one.

As Gustav fades, Hanna, Ike, and Josephine line up to potentially take aim at the US or Caribbean.

As Gustav fades, Hanna, Ike, and Josephine line up to potentially take aim at the US or Caribbean.

Gustav roared through the Gulf Coast, missing a worst-case scenario in New Orleans but causing plenty of damage elsewhere: coastal damage is spread all through Cajun country, and the Mississippi Coast. Heavy rains will continue, and many Louisianans may be without electric power for a week or more.

New Orleans Mayor Ray Nagin tagged the approaching Gustav as the "Mother of All Storms." Nagin, roundly criticized during Katrina as were his state and federal counterparts, effectively frightened his city into a successful evacuation.  In fact, emergency managers on all levels erred on the side of caution rather than repeat the sad blunders of Katrina. And, of course, the levees didn't fail. The bottom line was a measure of reassurance for New Orleans. Whether it was well-placed is another matter.

It's important to bear in mind that neither Gustav nor Katrina brought full fury to New Orleans. Katrina was a Category Three storm when it passed to the east of the city, forcing a wall of water into New Orleans and the Mississippi Coast. Gustav was a Cat Two when it passed far to the west of the city, which was barely on the fringe of hurricane-force winds. Tide gauges measured about a five-foot surge in Lake Ponchartrain yesterday. So the real bottom line may be that a bigger test still awaits the engineers, leaders, and people of New Orleans.

Next up is Hanna, forecast to be a weak hurricane making a U.S landfall Friday, possibly at or near Savannah, Georgia. It's been 110 years since Savannah took a direct hit, the longest lucky streak of any major coastal U.S. city in the hurricane zone. Hanna is now bringing heavy rain to Haiti (as of midday Tuesday).

After that, Ike. While it's too soon to give any definitive forecast for the tropical storm, it could be headed to the Gulf of Mexico, according to several long-range models.

Today the National Hurricane Center named a new one: Josephine, forming as a tropical storm off the African coast, could cross the ocean to threaten in 7 to 10 days.

Peter Dykstra Executive Producer CNN Science, Tech & Weather

Filed under: hurricanes • Weather

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