On May 20, 2013, NASA and NOAA satellites were routinely monitoring the weather system that generated severe weather in the south-central United States and spawned the devastating Moore, Oklahoma tornado. This post contains four images from that routine monitoring from space. The first image below – from NASA’s Aqua satellite – captured a visible image of the storm. NASA says this image provided a detailed look at the supercell thunderstorm that spawned the tornado.

Natural color image of Moore, Oklahoma tornado on May 20, 2013 from NASA’s Aqua satellite. NASA image via Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC.

NOAA’s GOES-East (Geostationary Operational Environmental Satellite), which continually monitors weather activity and helps provide our weather forecasts, acquired this view of the severe storm system on May 20. NASA GOES-13 image.

Meanwhile, NOAA’s GOES-13 satellite acquired the image above in the course of doing what it always does – providing continuously updated satellite imagery depicting the movement of weather systems across the U.S. Look here for a downloadable animation that runs from 10:45 a.m. through 6:45 p.m., Central Daylight Time.

In this image, taken at night after the tornado passed through Moore, moonlight is illuminating the tops of the storm clouds. Image Credit: William Straka III, University of Wisconsin, CIMSSData Credit: University of Wisconsin

After the tornado, NASA-NOAA’s Suomi NPP satellite acquired the image above. Rob Gutro of NASA’s Goddard Space Flight Center wrote:

The side lighting from the moon showed towering overshooting tops of the storm, along with the gravity waves associated with the intense convection. In addition, the day night band (DNB), which sensitive to low light levels at night, can see features which are illuminated by the moon as well as emissive light sources, such as city lights and fires. In addition, the Day-Night-Band or DNB can detect lighting from the storm tops, which appear as the rectangular shapes in the image. This streaking is a result of the time it takes the sensor to scan compared to the short intense lighting flash.

Whole Earth image of May 20, 2013 tornado in Oklahoma from NOAA’s GOES-13 satellite. Image Credit: NASA/NOAA GOES Project, Dennis Chesters

And finally here’s an image of the whole Earth, above. It’s from NOAA’s GOES-13 satellite and shows the weather systems across the entire planet at the time of the devastating storm. The image is from at 20:45 UTC (2:45 p.m. CDT or 1945 UTC) on May 20. It shows the storm system in the south-central U.S. that generated Moore, Oklahoma tornado. The Moore twister was an F-4 tornado (winds between 166 and 200 mph) that touched down around 2:52 p.m. CDT and dissipated around 3:36 p.m. CDT.

See more space images of the May 20 severe storms in the south-central U.S. on this NASA Flickr page

Bottom line: Four images from space, from NASA and NOAA satellites, of the Moore, Oklahoma tornado on May 20, 2013.

While hydrogen is ubiquitous in the environment, producing and collecting molecular hydrogen for transportation and industrial uses is expensive and complicated. Just as importantly, a byproduct of most current methods of producing hydrogen is carbon monoxide, which is toxic to humans and animals.

The Duke engineers, using a new catalytic approach, have shown in the laboratory that they can reduce carbon monoxide levels to nearly zero in the presence of hydrogen and the harmless byproducts of carbon dioxide and water. They also demonstrated that they could produce hydrogen by reforming fuel at much lower temperatures than conventional methods, which makes it a more practical option.

Credit: Shutterstock / mypokcik

Catalysts are agents added to promote chemical reactions. In this case, the catalysts were nanoparticle combinations of gold and iron oxide (rust), but not in the traditional sense. Current methods depend on gold nanoparticlesâ?? ability to drive the process as the sole catalyst, while the Duke researchers made both the iron oxide and the gold the focus of the catalytic process.

The study appears online in the May issue of the Journal of Catalysis, viewable at http://www.sciencedirect.com/science/article/pii/S0021951712004204.

“Our ultimate goal is to be able to produce hydrogen for use in fuel cells,” said Titilayo “Titi” Shodiya, a graduate student working in the laboratory of senior researcher Nico Hotz, assistant professor of mechanical engineering and materials science at Duke’s Pratt School of Engineering. “Everyone is interested in sustainable and non-polluting ways of producing useful energy without fossil fuels,” said Shodiya, the paper’s first author.

Fuel cells produce electricity through chemical reactions, most commonly involving hydrogen. Also, many industrial processes require hydrogen as a chemical reagent and vehicles are beginning to use hydrogen as a primary fuel source.

“We were able through our system to consistently produce hydrogen with less than 0.002 percent (20 parts per million) of carbon monoxide,” Shodiya said.

The Duke researchers achieved these levels by switching the recipe for the nanoparticles used as catalysts for the reactions to oxidize carbon monoxide in hydrogen-rich gases. Traditional methods of cleaning hydrogen, which are not nearly as efficient as this new approach, also involve gold-iron oxide nanoparticles as the catalyst, the researchers said.

“It had been assumed that the iron oxide nanoparticles were only ‘scaffolds’ holding the gold nanoparticles together, and that the gold was responsible for the chemical reactions,” Sodiya said. “However, we found that increasing the surface area of the iron oxide dramatically increased the catalytic activity of the gold.”

One of the newest approaches to producing renewable energy is the use of biomass-derived alcohol-based sources, such as methanol. When methanol is treated with steam, or reformed, it creates a hydrogen-rich mixture that can be used in fuel cells.

“The main problem with this approach is that it also produces carbon monoxide, which is not only toxic to life, but also quickly damages the catalyst on fuel cell membranes that are crucial to the functioning of a fuel cell,” Hotz said. “It doesn’t take much carbon monoxide to ruin these membranes.”

The researchers ran the reaction for more than 200 hours and found no reduction in the ability of the catalyst to reduce the amount of carbon monoxide in the hydrogen gas.

“The mechanism for this is not exactly understood yet. However, while current thinking is that the size of the gold particles is key, we believe the emphasis of further research should focus on iron oxide’s role in the process,” Shodiya said.

Via Duke

This molecule is based on a natural protein present in human breast milk, which has been found to have strong and wide-ranging tumour killing properties when bound to certain lipids. Lipids are organic molecules like amino acids and carbohydrates, made up of carbon and hydrogen, and help to store energy and to form biological membranes.

The protein-lipid molecule complex, is known as HAMLET, which stands for Human Alpha-lactabumin Made Lethal to Tumour cells. It has been proven to be safe and effective as it only targets tumor cells, leaving healthy human cells intact.

HAMLET has most recently been shown to successfully suppress colon cancer in laboratory mice.

The scientists have also successfully identified and isolated specific components of HAMLET called peptide-oleate bound forms, which have the tumor-killing effect. Peptides are short chain amino acids commonly found in the human body.

These latest breakthroughs are led by Professor Catharina Svanborg and Dr Manoj Puthia from Lund University, Sweden, and Professor Gerhard Grüber from NTU’s School of Biological Sciences. The HAMLET complex was first discovered by Professor Svanborg’s research group.

The findings were published recently in Gut and in PLoS ONE, two top ranking peer-reviewed academic journals. The researchers found that laboratory mice genetically modified to develop colon cancer, were protected to a large extent when fed with HAMLET-laced water. This suggested that HAMLET was killing emerging tumor cells faster than these cells could grow and proliferate.

On the new concept of a synthetic version of the tumor-killing molecule, Prof Grüber said, “By studying the original protein, we have and will continue to identify key components to make a synthetic peptide, a short-chain amino acid, carrying the properties of HAMLET and yet more resilient than the original protein complex.”

“By synthetically constructing the key components, this helps the peptide to be much more resilient and to ‘survive’ in different environments, such as in the human body or in drinking water, which is an ideal delivery medium, before it reaches its tumor target.”

The ability to recreate HAMLET in synthetic form opens up possibilities of turning it into a drug to kill tumors.

Cancer cells. Credit: Shutterstock / Shebeko

Next steps

Prof Svanborg, who is a doctor and a scientist, said she had seen promising results from the human trials using HAMLET in Sweden.

“We are now ready to test HAMLET as a therapeutic and preventive agent in colon cancer, especially in families with the genetic predisposition, where preventive options are limited,” Prof Svanborg said.

“After completing the various clinical trials, we hope to develop a commercially available product for doctors’ use for cancer treatment in the next five to ten years,” she added.

The two lead scientists added that they are also looking to trial HAMLET in Singapore and are in talks with local institutions and industry.

Via Nanyang Technological University

At False Bay, South Africa, great white sharks are infamous for their dramatic attacks on fur seals. They propel from the ocean depths towards their prey at such great speed that they breach the ocean surface, often with a seal clamped between rows of teeth in their enormous mouth. But the seals aren’t the only source of food for the sharks. Scientists have uncovered new evidence that scavenging on dead whales is a little-known but significant food source for great whites. A team led by Chris Fallows of Apex Expeditions at Cape Town, South Africa reported these findings in April 2013 in the journal PLOS ONE.

Fallows and his team reported detailed extended observations of four whale scavenging events by great whites at False Bay. Some of the sharks were individuals known to the research team, either from color-coded tags attached during previous studies, or from unique body markings.

A 4.5 m (14.8 ft) white shark removed a 20 kg (44 lbs) chunk of flesh, sinew, and blubber by performing lateral headshakes. Courtesy C. Fallows, et al.

Typically, the sharks approached a dead whale slowly, swimming around it and mouthing it at different parts of the carcass. Feeding usually started at the extreme rear body and tail of the whale, then proceeded to blubber-rich sections of the carcass. The sharks sank their teeth into the whale, tearing out flesh by shaking their heads from side to side. In one extraordinary instance, a 4 meter-long (13 foot) shark entered inside the carcass of a Bryde’s whale, extracting and eating a near-term fetus.

The sharks often regurgitated large pieces of blubber, then returned to the carcass to continue feeding. They did this, the scientists speculated, to replace what they had earlier consumed with more nutritious energy-packed blubber. A shark could continue feeding for over 6 hours, until it reached a point where it could eat no more. As if intoxicated, the sharks could not lift their heads above the water, while half-heartedly nudging and mouthing the carcass, seeming too weak to bite and tear at the flesh. Eventually, they would give up, floating to the depths.

White shark scavenging the rear body and tail of a Bryde’s whale. Courtesy C. Fallows, et al.

Meanwhile, the seals were catching a break. When a whale carcass was present in waters off Seal Island, the rate of seal predation by great whites dropped significantly as the sharks were otherwise distracted.

While feeding on a dead whale, great white sharks did not display any aggression, even when there were as many as eight of them simultaneously tearing into the carcass, often bumping into each other. They did, however, display a social hierarchy, with the largest sharks getting the choicest blubbery parts of the whale. Smaller great whites, 3 to 4 meters (9.8 to 13 feet) long, lingered back, not daring to feed with the big guys, instead, grabbing pieces of drifting blubber.

This white shark removed blubber around the jaw of a southern right whale carcass. Courtesy C. Fallows, et al.

A 4.5-m (14.8-ft) white shark removed a 20-kg (44-lb) chunk of flesh, sinew, and blubber from a whale by performing lateral headshakes. Courtesy C. Fallows, et al.

Great white sharks that occupy the waters off Seal Island, that prey on fur seals, are generally about 3.5 meters (11.5 feet) in length, 4 meters (13 feet) at most.

The scientists believe that sharks longer than 4 meters are absent around Seal Island because the amount of effort expended in catching the agile seals exceed the nutrient payoff. Yet, large sharks, as much as 5 meters (16.4 feet), were showing up to feed on the whale carcass. Where were these larger sharks coming from?

It appears that large great white sharks that outgrew the waters around Seal Island didn’t go very far. They are likely off the coast of the Western Cape, feeding on dead or weak cetaceans that migrate through those waters. Sharks have an excellent sense of smell, and could have picked up the odors from whale carcasses in Cape False. In fact, the team found there were more sharks feeding on a carcass when the wind was blowing the scent trail out to sea, drawing the sharks into Cape False.

White sharks scavenging on whales from R.J. Dunlap Marine Conservation on Vimeo.

Seal Island, at the foot of False Bay, is home to about 60,000 Cape fur seals. Each winter, between May and September, adult white sharks patrol the waters off the island, preying on seals during their foraging expeditions at sea. Observations of the sharks feeding on carcasses at Cape False in South Africa suggest that sharks too large to go after resident Cape fur seals could be patrolling coastal waters off the Western Cape, preying on weakened whales and feeding on dead whales.

Thus our understanding of great white sharks’ feeding habits may be misled by the sharks’ well-known predatory ferocity. Scavenging of whale carcasses by great white sharks, while rarely observed, may be happening more frequently than previously thought.

Bottom line: New research shows that great white sharks scavenge on dead whales for food. A team led by Chris Fallows of Apex Expeditions at Cape Town, South Africa reported these findings in April 2013 in the journal PLOS ONE.

Check out Andrew Shurtleff’s stunning time-lapse video showing the world as viewed in near-infrared. The light-sensitive chips of digital cameras can sense these wavelengths outside human vision. With the right kind of video editing, that infrared world comes alive – like a planet painted from pure ice. The leafy material appears white due to its intense reflection of infrared light.

May 21, 2013, 900 a.m. CDT (May 21 at 1400 UTC) — Officials have now lowered the death toll after a two-mile-wide EF-4 tornado swept through tracts of homes, two schools and a hospital in Moore, Oklahoma, a suburb of Oklahoma City, yesterday afternoon. The medical examiner’s office has revised the death toll from an anticipated 91 deaths earlier today, to at least 24 deaths, including 9 children. Officials say the lower number is due to unintentional over-counting of fatalities in the immediate aftermath of the tornado. The National Weather Service said the tornado was on the ground in Moore for 40 minutes. Emergency crews spent last night at a school in Moore, trying to rescue students and staff trapped by falling debris. The tornado turned hundreds of homes in some neighborhoods in Moore – in southwest Oklahoma City – to rubble and set fires. It is reported to have “wiped out entire neighborhoods” and to have left a wide path of debris.

Text ‘redcross’ to 90999 to donate $10 for Oklahoma disaster relief. You’ll receive a confirmation via text.

The Storm Prediction Center has issued another moderate risk – mainly a wind damage threat, but tornadoes are possible, too – in northeast Texas, northern Louisiana, and into central/southern Arkansas. Look here for the storm outlook.

Everything you need to know: How to stay safe in a tornado

Debris ball on radar indicated a tornado was coming.

Advance warning systems for May 20 tornado worked.

May 20 tornado is one of several in the central U.S. in past few days.

A previous deadly tornado in Moore.

More photos and videos of May 20 tornado in Oklahoma.

View live video and rescue efforts in Oklahoma from WFMY-TV

Oklahoma County live audio feeds

Red Cross “Well and Safe” website – let your family and friends know.

Mile-wide tornado spent 40 minutes on the ground in Moore, Oklahoma, a suburb of Oklahoma City, on May 20, 2013. Image is a video still from CBS News.

View larger. | A debris ball created by the tornado showed up on radar, giving advance warning of its deadly power.

Preliminary track of May 20, 2013 Newcastle-Moore, Oklahoma, tornado. Graphic prepared by the National Weather Service Weather Forecast Office in Norman, Oklahoma.

Moore, Oklahoma, a suburb of Oklahoma City, in the central part of the state.

Debris ball on radar indicated a tornado was coming. At 3:21 p.m. CDT on May 20, a supercell was pushing right towards Moore, Oklahoma. It was apparent on Doppler radar as the storm was indicating a debris ball. A debris ball simply indicates debris that is lofted into the air by a tornado. The debris could be anything: pieces of houses, vehicles, paper, insulation, trees, etc. The radar beam hits this debris, and it picks up very high reflectivities. The debris ball simply shows a circular area of very highly concentrated reflectivity that shows up in dark red and purple. At one time, the debris ball was nearly two miles wide. It does not mean the tornado itself was two miles wide, but it definitely indicates that the tornado was at least a mile wide as it hit. Meanwhile, the radial velocity image on the right simply shows the strong couplet signature indicating very strong winds moving away and towards the radar. It indicates the strong rotation within that single point, and that is where the tornado is located.

Advance warning systems for tornado worked. It’s easily possible that this horrible event might have been even more deadly, but for the fact that it was warned well in advance. The Storm Prediction Center issued a moderate risk for severe weather across central and eastern Oklahoma for May 20. Many were aware that a volatile situation could take place. Meteorologists cannot determine hours in advance exactly where a storm will produce a tornado, but we can be weather aware and be knowledgeable that something could develop. With that said, the National Weather Service from Norman, Oklahoma was able to issue a warning in advance and provide the city of Moore, Oklahoma with some time to prepare. According to the NWS in Norman, Oklahoma, the Newcastle-Moore Oklahoma City Tornado was on the ground for approximately 40 minutes. The tornado warning they issued was in effect for 16 minutes before the tornado developed.

May 20 tornado is one of several in the central U.S. in past few days. Look here for video and photos of May 18-19 tornados in central U.S.

A previous deadly tornado in Moore. Moore, Oklahoma was hit by a previous tornado on May 3, 1999. The 1999 Bridge Creek–Moore tornado was an extremely powerful F5 tornado. According to the Storm Prediction Bureau, the tornado lasted one hour and 25 minutes, covering 38 miles (61 km), destroying thousands of homes, killing 41 people, leaving $1 billion in losses behind and ultimately ranking as the third-costliest tornado on record, not accounting for inflation. By the way, Moore residents had 32 minutes lead time – advance warning from meteorologists – to get ready for the 1999 tornado. Although the lead time was somewhat less in the May 20, 2013 event, both the 1999 and the 2013 tornados in Moore, Oklahoma benefited from more lead time than the averages earlier in the 1990s, around 5 minutes.

More photos and videos of May 20, 2013 tornado in Oklahoma, below.

Television coverage from the Associated Press, below, shows flattened buildings and at least one fire after a mile-wide tornado tore through the Oklahoma City area. Homes and buildings in Moore, Okla., were reduced to rubble and vehicles littered roadways.

The May 20, 2013 tornado as it passed south of Oklahoma City. Photo by Ks0stm via Wikimedia Commons.

The images below are video still from KFOR-TV. Local television stations typically provide the best, sometimes the only, immediate coverage of events such as this one.

Screen capture of May 20, 2013 Moore, Oklahoma tornado damage from KFOR-TV.

Screen capture of May 20, 2013 Moore, Oklahoma tornado damage from KFOR-TV.

Screen capture of May 20, 2013 Moore, Oklahoma tornado damage from KFOR-TV.

We will update on the May 20, 2013 tornado as more information becomes available.

Bottom line: A two-mile-wide tornado spent 40 minutes on the ground in Moore, Oklahoma, yesterday (May 21, 2013). Moore is a suburb of Oklahoma City. The tornado ripped through tracts of homes, two schools and a hospital. Officials have confirmed at least 24 deaths and hundreds of injuries from the massive tornado.

The Alpha Centauri system is said to be the closest star system to our sun. On our sky’s dome, we see this multiple system as a single star – the third-brightest star visible from Earth.

Alpha Centauri A and B are a double-star system, and a third star Proxima – whose location with respect to the other two is indicated here by arrow – might or might not be gravitationally bound to them. Proxima is the closest star to Earth. Image via the European Southern Observatory.

Whoa! Earth-size planet in Alpha Centauri system

Alpha Centauri is part of a double, or triple, star system. The two main components are Alpha Centauri A and Alpha Centauri B. The third star, a red dwarf called Proxima Centauri, is thought to be about 4.22 light-years distant and is actually our sun’s closest neighbor among the stars. Is it part of the Alpha Centauri system? The actual status of Proxima as a system member is unclear. It might simply be passing nearby but not part of the system, or it might be gravitationally bound. Still, we say – and others say – that Alpha Centauri is the closest star to our solar system, with the assumption that Proxima is a true part of the Alpha Centauri system.

If you looked through a small telescope at the Alpha Centauri system, you’d see the two main stars, but you wouldn’t see Proxima Centauri. It’s too faint and appears too far (4 diameters of the full moon) away to be easily recognized at part of the system.

Taken by itself, Alpha Centauri A is the fourth-brightest star seen from Earth, just slightly outshone by Arcturus. However, the combined light of Alpha Centauri A and B is slightly greater than Arcturus, so in that sense it is the third-brightest. These stars are an average of 4.3 light-years away.

A comparison of the sizes and colors of the stars in the Alpha Centauri system with our sun. Via Wikimedia Commons.

Yellow Alpha Centauri A is the same stellar type as the Sun (G2), although a bit larger. It looks bright in our sky because of its nearness to Earth. Just a few degrees away, the star Hadar (a separate star sometimes called Beta Centauri, not to be confused with Alpha Centauri B) appears dimmer in our sky than Alpha Centauri. But in fact, Hadar is much farther away at 525 light-years. So you see that Alpha Centauri is not a fabulously brilliant star, as stars go.

Alpha Centauri’s surface temperature is a few degrees Kelvin less than our sun (that is, about 5770 k), but its greater diameter (about 25% more than the sun) and the overall larger surface area gives it a luminosity nearly 1.6 times that of our star.

The smaller member of the system – orangish Alpha Centauri B – is slightly smaller than our sun, with a spectral type of K2. With lower temperature (about 5,300 K) and only half the luminosity of the sun, B would shine as the 21st brightest star in all the heavens by itself.

These two brighter components of the system orbit a common center of gravity once every 80 years. The orbit is notably elliptical, with average distance between the two stars of about 11 A.U., with one A.U. being one Earth-sun distance.

Faint red Proxima Centauri – at only 3,100 K and 500 times less bright than our sun – is nearly a fifth of a light year from Alpha Centauri A and B. This great distance is what calls into question its status as part of a triple star system.

You must be south of 29 degrees N. latitude even to glimpse Alpha Centauri. This chart shows the view from Earth’s Southern Hemisphere. From there, Alpha Centauri’s constellation – Centaurus the Centaur – is circumpolar. It circles around and around the sky’s south pole.

How to see it

Unluckily for us in the Northern Hemisphere, Alpha Centauri is located very far to the south on the sky’s dome. Most North Americans never see it. The cut-off latitude is about 29 degrees north, and anyone north of that is out of luck. In the U.S. the line passes near Houston and Orlando, but even from the Florida Keys, the star never rises more than a few degrees above the southern horizon. Things are a little better in Hawaii and Puerto Rico, where it can get 10 or 11 degrees high.

Northern Hemisphere dwellers might glimpse Alpha Centauri at roughly 1 a.m. (local Daylight savings time) in early May. That is when the star system would be highest above the southern horizon. By early July, the system reaches its highest point to the south at nightfall.

Meanwhile, in Australia and much of the southern hemisphere, Alpha Centauri is circumpolar, meaning that it never sets. Also called Rigel Kentaurus or Rigel Kent, this neighboring star is probably the most famous star that almost no one in the northern hemisphere has ever seen.

For northern observers, there really are no good pointer stars to Alpha Centauri. When the bright star Arcturus is high overhead, Alpha Centauri might low in your southern sky, assuming you are south of 29 degrees N. latitude.

If you are in the Southern Hemisphere, you can identify Alpha Centauri using the Southern Cross as a guide. A line drawn through the crossbar of the Cross, eastward, first comes to Hadar (Beta Centauri), then Alpha Centauri. Image via AstroBob

Observers in the tropical and subtropical regions of the Northern Hemisphere can find Alpha Centauri by first identifying the distinctive Southern Cross. A short line drawn through the crossbar (Delta and Beta Crucis) eastward first comes to Hadar (Beta Centauri), then Alpha Centauri.

History and Myth

Alpha Centauri is the brightest star in the southern constellation Centaurus the Centaur. Two alternative names for this star, Toliman and Bungula, are rarely used any more. The derivations are somewhat questionable, but Toliman may be from the Arabic for ostriches and Bungula apparently derives from Latin meaning hoof.

Thousands of years ago, a motion of Earth called precession – which causes the identity of the Pole Star to change over time – caused Alpha Centauri to appear higher in the sky as seen from the Northern Hemisphere than it does now. But it was still far to the south and often difficult to see.

Centaurus the Centaur via ConstellationofWords.com

Classical myth-makers didn’t spend much time with this constellation, although it was thought to represent an uncharacteristically wise centaur that figured in the mythology of Heracles and Jason. The centaur was accidentally wounded by Heracles, and placed into the sky after death by Zeus.

Alpha Centauri itself marked the right front hoof of the Centaur, although little is known of its mythological significance, if any. Ancient Egyptians revered it, and may have built temples aligned to its rising point. In southern China it was part of a star group known as the South Gate.

Alpha Centauri’s position is RA: 14h 39m 41s, dec: -60° 50′ 07″

How long would it take to get to Alpha Centauri?

This post outlines what you need to know to stay safe during a tornado.

First, some tornado basics and vocabulary.

What’s the difference between a tornado watch and a tornado warning?

When a tornado watch is issued, it means conditions are favorable for the formation of this type of storm. A tornado watch means that – in the determination of weather experts – the atmosphere has all of the ingredients it needs to make and produce a tornado. It does not mean imminent storms are on the way, or that a storm has been sighted on the ground. When a tornado watch is issued, you need to do just that: watch the weather. Know where a safe shelter is, and be prepared to act quickly in case a warning is issued.

Pekin, Indiana tornado March 2, 2012 via John's World

When a tornado warning is issued, it means a storm is approaching your area. You must take shelter – fast. Tornado warnings are issued when the National Weather Service indicates a storm with strong rotation on Doppler Radar, or if there is confirmation that a tornado is on the ground.

If you are in the tornado’s path, you must immediately drop whatever you are doing and proceed to a safe spot.

For more information regarding the difference between a tornado watch and tornado warning, check out this great NOAA video:

I can’t emphasize enough that you should stay alert to the weather in your area. Meteorologists can forecast severe weather events three to five days out. If it is a significant event, meteorologists will automatically send out updates via the Storm Prediction Center and through local National Weather Services so that the media and the public can prepare. If you live in a moderate or high risk area for severe weather, you should take these threats very seriously. If you live in a mobile home, perhaps you should relocate and stay at a friend’s house that is safe and sturdy when storms are forecast for your area.

How do I determine a safe spot during a tornado?

Everyone lives in houses that are constructed differently, and many people do not have a basement. If you live in a place that has tornadoes, it is very important that you have a tornado plan and practice tornado drills. Typically, tornado drills are only implemented at school. It would be wise to practice these drills at our homes, businesses, and at amusement parks, sporting events, and shopping centers. Here’s a guide put together by Aneela Qureshi of the University of Georgia (see below), with information from NOAA:

An EF-4 tornado crossed Concord, Alabama. The only thing remaining from this building was the bathroom, and bathrooms are often the safest place to be. Image Credit: Matt Daniel

Standard houses/homes during tornadoes:

• Have a designated place to go. The best place is a specially built storm shelter. Next best solution is in a central room (like a bathroom or a closet) in the basement. If you don’t have a basement, the next best place is a central room in the lowest level of the house. Avoid windows, and try to have as many walls between you and the tornado as possible!
• If you locate in a bathroom, get in the bathtub and throw cushions on top of you. Out of the many tornado ravaged areas I visited, the bathtub was always the last thing standing.
• Put together an emergency supply kit, including items such as a battery operated weather radio, flashlight, batteries, first aid items, and bottled water. Keep it in a place you can easily grab it (preferably your designated shelter). Make sure cell phones are fully charged.
• If you have a whistle, have it on you. If you end up being trapped in debris, a whistle could let others know you are alive and need assistance.
• Be able to protect your head! Many tornado-related fatalities are due to head trauma, so have helmets or other sturdy head coverings available.
• Have regular tornado drills so you and your family know exactly what to do and where to go.
• When the tornado warning is issued, get to your safe place immediately! Don’t waste time trying to watch or record the tornado. The most important thing is to keep you and your family safe.

A relatively weak tornado (EF-1) knocked this mobile home on its side in Madison, Georgia on April 27, 2011. It does not take very strong winds to hurt or damage mobile homes. Image Credit: Matt Daniel

Mobile homes during tornadoes:

• Mobile homes, even ones that are tied down, are never safe during a tornado!
• Find a storm shelter ahead of time – whether it’s a designated shelter, a nearby friend’s house, etc. Don’t wait until the last minute to do this!
• Leave when you hear a tornado watch is issued and get to your safe place.
• If necessary, be prepared to take shelter in a low area, such as a ditch. Cover your head and watch out for flooding.

Cars during tornadoes:

• The best thing to do is pull over, get out of your car, and get to a safe shelter, such as a nearby building.
• If no shelter is available, lie down in a low area, such as a ditch. Tornado winds are the lowest right at the ground. Be mindful of other storm-related hazards, such as flooding. Cover the back of your head and neck.
• What about highway overpasses? Tornado movies all seem to have a scene where somebody takes shelter under a bridge or overpass and walks away unscathed. Sounds like a great idea, right? Wrong. Overpasses are actually very dangerous during a tornado. Winds get stronger above ground, and the narrow opening under an overpass can create a wind tunnel, significantly increasing the wind speeds and flinging deadly debris missiles. Three people died, and many more were seriously injured, during the May 3, 1999 tornado outbreak in Oklahoma when they took shelter under highway overpasses. Check out this presentation from the folks at the National Weather Service and National Severe Storms Laboratory for more information.
• Try to avoid travelling if there is a big threat for severe storms and tornadoes!

School or work during tornadoes:

• Follow the building policies (make sure you know them ahead of time).
• Get to a designated shelter if possible. Otherwise go to the lowest level.
• Stay in the interior away from windows, and avoid large open rooms such as gymnasiums or auditoriums.
• Crouch down low and cover your head.

Alabama tornado March 1, 2012 via ibtimes.com

Shopping centers during tornadoes:

• Find out ahead of time if a shopping center has a severe weather plan, and follow the plan.
• Get to a designated shelter if possible. Otherwise go to the lowest level.
• Stay in the interior away from windows, and avoid large open rooms.
• Most stores will take you to the center of the building away from shelves that could hurt you. A bathroom is a great alternative.
• If you know there is a good risk of severe weather in your area, avoid the roads and shopping. This is the best preventative measure you can take to insure your safety.

What to do after a tornado:

• Remain calm. Stay in your shelter until the storm has passed.
• Be mindful of other weather hazards, such as hail, flooding and lightning.
• Use a flashlight, not candles (in case of broken gas pipes).
• Check people for injuries. Begin first aid, or get help if necessary.
• If your home/shelter is no longer a safe place to be, go somewhere that is. You may have to stay where you are until help arrives. Keep a whistle in your emergency kit in case you need to signal for help.
• Avoid downed power lines, debris, fallen trees and other hazards.

Here’s why you want and need a weather radio

So now that you know how to plan for tornadoes, what do you think is the best way to receive tornado warnings? Do you own a NOAA weather radio? Or do you, like many other people, depend on tornado sirens?

Image Credit: Walker Ashley at NIU

Time and time again, after a tornado hits we hear people saying:

I didn’t hear the sirens so I didn’t know we were in danger!

According to Jim Allsopp of the National Weather Service office in Chicago, Illinois:

Sirens are great. They serve a purpose, but they should not be your primary method of receiving warnings.

Between 1950-2005, 42% of killer tornadoes occurred at night. Image via wwaytv3.com

Yes, sirens are loud. They can be heard very clearly if you are outside. Sirens are not designed to be heard indoors or to wake people up in the middle of the night. Some of you are probably asking at this point:

Night? Don’t most tornadoes happen in the late afternoon or evening?

A lot of them do happen in afternoon or evening, but tornadoes can strike at night as well. Most U.S. states experience nighttime tornadoes, with the mid-South in the U.S. experiencing the greatest frequency. According to researchers at Northern Illinois University, these nighttime tornadoes are 2.5 times more likely to kill as those during the day. Between 1950-2005, 42% of killer tornadoes occurred at night. If you are home sleeping when one of these tornadoes hits, there is no way an outdoor siren is going to wake you up. Get a weather radio, or a weather radio app for your phone such as iMapWeather. You can get a good one for around $30. Program it to go off when your area is under a watch or warning. Keep it by your bedside so it will wake you up, and you can get to shelter immediately.

If you want to learn more about general weather safety, please visit the NWS Safety Guide. It includes ways of protecting yourself from other elements such as snow, heat, lightning, and floods.

Aneela Qureshi helped write this post. Thank you, Aneela!

A special thank you goes out to Aneela Qureshi who is a Ph.D. student in the Department of Geography at the University of Georgia. She contributed greatly to this article. About Aneela Qureshi: Qureshi has a strong background in both meteorology and education, along with extensive experience teaching about weather and weather safety to groups ranging from pre-K to adult, in both formal and non-formal settings (including one of the top 10 children’s science museums in the U.S.). Qureshi is very interested in weather safety, and her research is in winter weather hazards and preparedness in Georgia, especially what K-5 students know about these topics and how what they learn impacts their families’ safety behaviors.

Bottom line: Spring 2012 is here and that means we are in tornado season. This post outlines what you need to know to stay safe during a tornado: difference between watches and warning, safest places to be, what to do if you are not in a safe place, why you need a weather radio. Stay safe, everyone!

This devastating tornado grew to two miles across and stayed on the ground for 40 minutes in the Oklahoma City suburb of Moore yesterday.

Read about the Moore, Oklahoma tornado and its tragic consequences

Donate to the Red Cross to help the tornado’s victims or text ‘redcross’ to 90999 to donate $10 for Oklahoma disaster relief. You’ll receive a confirmation via text.

These are the 10 deadliest tornadoes since 1900, according to AP and the National Oceanic and Atmospheric Administration.

— 695 deaths. March 18, 1925, in Missouri, Illinois and Indiana.
— 216 deaths. April 5, 1936, in Tupelo, Miss.
— 203 deaths. April 6, 1936, in Gainesville, Ga.
— 181 deaths. April 9, 1947, in Woodward, Okla.
— 158 deaths. May 22, 2011, in Joplin, Mo.
— 143 deaths. April 24, 1908, in Amite, La., and Purvis, Miss.
— 116 deaths. June 8, 1953, in Flint, Mich.
— 114 deaths. May 11, 1953 in Waco, Tex.
— 114 deaths. May 18, 1902 in Goliad, Tex.
— 103 deaths. March 23, 1913, in Omaha, Neb.

May 22, 2011 tornado in Joplin, Missouri via TornadoChasers.com

A radar image of the supercell that produced the devasting tornado in Joplin, Missouri on May 22, 2011. Base reflectivity is on the left and storm relative velocity on the right. The area of high reflectivity just to the right of the Joplin label is debris lofted into the air by the tornado. Image via Wikimedia Commons.

Reposted from Caitlin Dewey via the Capitol Weather Gang at the Washington Post

Bottom line: Ten deadliest U.S. tornadoes since 1900.