Researchers Hope New Technology Can Increase Warning Times, Save Lives
By ASHLEY PHILLIPS and NED POTTER
July 25, 2008 —
As a record-breaking and increasingly deadly tornado season wreaked havoc across middle America this summer, researchers have been testing a new, high-tech radar system that could help forecasters better pinpoint when, where and how a twister or any other storm for that matter will strike.
The United States has the most powerful radar network in the world -- a national system called NEXRAD. But even so, the average tornado warning comes only 12 minutes before the storm strikes -- and three quarters of the warnings are false alarms.
"We don't want to have people who are waiting 10, 15, 20 minutes, and then nothing happens," said Kevin A. Kloesel, associate dean of the College of Atmospheric and Geographic Sciences at the University of Oklahoma.
To that end, university researchers, in conjunction with the National Oceanic and Atmospheric Administration, which runs the National Weather Service, have been quietly testing a new high-tech system of radars that can see what current NOAA radars can't: storm activity that is close to the ground.
"The National Weather Service operates a radar network and those radars are located hundreds of miles apart. They cover huge areas, are large and do surveillance scanning over the area they cover," Kloesel said. "The problem with large scanning radar is that the farther you look out when you send a beam straight out, the Earth is actually curving away from it as you get farther and farther away. When you get 90 to 100 miles out, that beam is sensing the storm at 8,000 to 10,000 feet."
According to Kloesel, who has worked on the project since it began six years ago, earth curvature creates an "umbrella" close to the ground that radars can't see; this new system, called Collaborative Adaptive Sensing of the Atmosphere (CASA), is designed to look under that umbrella, where severe weather, like tornadoes, and hail actually form.
In order to achieve that, CASA is built around a system of radars that are low to the ground, on cell phone towers, for example, and scan smaller areas.
"We see what's going on down low much better than you can with the existing technology," Kloesel said.
Unlike existing weather radars, however, the CASA radars also communicate with one another, so if a tornado is tearing through an Iowa town for example, the radars can communicate with each other and follow it as it travels its path instead of continuing to examine random areas that aren't experiencing any storm activity.
"The current system of radars [doesn't] interact with one another. It just sits and spins," Kloesel said. "[With CASA], you can have multiple radars sensing the same storm. They work in many instances like air traffic controllers."
Kloesel doesn't view CASA as competition for current radar technology, but rather a great way for NOAA to get an even clearer picture from both the ground and the air of what's happening in a storm.
"Storms are three-dimensional, so even though a storm might be producing a tornado, the current technology is going to [only] give us a good look at what's going on in the upper part of that atmosphere," he said.
CASA could be especially helpful in areas that are prone to severe weather, like Houston, a city that often floods the radars can accurately report rainfall or other rain-related activity, in any part of tornado alley.
Another area where CASA could help? With warnings. Currently, the National Weather Service only delivers warnings when a tornado is detected. When a tornado warning is issued, for example, residents have an average of 12 minutes before the tornado hits. Some storm victims had even less than that. Like residents in Iowa and neighboring Kansas on June 11, when a series of tornados swept through. Four people were killed at a Boy Scout outing in Iowa, where some survivors said they had only three or four minutes notice.
Currently, before issuing a warning, the weather service often issues a less imminent tornado watch, that usually covers a wide area that experts say too many residents ignore.
"Sometimes people have to take a little more care," said Penn State meteorologist Jay Searles. "If people aren't able to look and take a little personally responsibility, it is a little hard to do. Educating yourself can really aid or help prevent disasters from happening as far as loss of life."
With CASA on the other hand, forecasters could do a "warning on forecast" model. Because the radars are watching what's happening with weather so close to the ground, forecasters would be able to issue warning with pinpoint accuracy up to two hours ahead of time where and when a tornado is likely to strike, according to Kloesel.
"We hope to be able to lower the false-alarm rate from the current 75 percent, maybe down to 10 or 20 percent," said Kelvin Deoegemeier, a professor of meteorology at the University of Oklahoma.
The study is facing a funding review from the National Science Foundation later this year and questions of infrastructure and cost are likely to be asked, said Kloesel, who declined to give cost estimates, saying they were out of date and not ready to be published. But whatever the cost, he says that as far as the researchers are concerned, the system is ready to be used.
"When you visit other states -- Texas, Wyoming -- they're clamoring for radars like this," said Jerry Brotzge, operations director for the CASA project at the University of Oklahoma. "They're willing to pay out of their own city money to buy a radar like this."WEATHER NOTE
|Tornadoes: Basic What-To-Dos|
|Tornadoes are the most violent storm and one of Earth's most dangerous catastrophes. Whirling winds usually exceed 100mph and can reach speeds of 300mph. An average of 1,000 tornadoes spin up beneath thunderstorms in the USA each year.|
Tornadoes can occur any time of the year but they are most rampant during USA's spring season because spring brings favorable tornado conditions.
The National Weather Service's Glossary of Meteorology defines a tornado as "a violently rotating column of air in contact with the ground and pendant from a thunderstorm." The thunderstorm is the first step in the formation of a tornado. If other weather conditions are right, the thunderstorm will spin out more tornadoes and cast catastrophe in land.
In the US, it damages the central and mountain state areas stretching from Texas to Nebraska. These states include Iowa, Colorado, Indiana, Illinois, Missouri, Oklahoma and Arkansas (known as Tornado Alley). In fact, tornadoes have already occurred in other states in the East Coast and West Coast but not as violent as what is normally occurring in the central and mountain states.
The six-tiered Fujita Scale ranks the damage that tornadoes make. F0 and F1 tornadoes on the scale are considered “weak” causing minimal to moderate damage with winds from 40-12 mph. F2 and F3 tornadoes are considered strong, packing winds of 113-206 mph that can cause major, severe damage. F4 and F5 tornadoes are classified with winds exceeding 206 mph.
Weak tornadoes travel in short distances for 10 minutes or less. Violent tornadoes, however, lasts for hours and can travel more than 100 miles.
Tornadoes can come without warning but there is always a tornado warning. Tornado warning means that a tornado has been sighted. If it is issued in your area, seek underground storm shelter immediately and bring emergency necessities like aid kits and important documents. Aid kits – first aid items, water, food, flashlight, transistor radio, batteries, and waterproof containers. Important documents – an inventory of your belongings, appliances, furniture, fixtures, for insurance purposes, and documents like birth certificates, etc.
BEFORE THE TORNADO…
Know the signs of a tornado: Weather forecasting science is not perfect and some tornadoes do occur without a tornado warning. There is no substitute for staying alert to the sky. Besides an obviously visible tornado, here are some things to look and listen for: strong, persistent rotation in the cloud base; whirling dust or debris on the ground under a cloud base -- tornadoes sometimes have no funnel; Hail or heavy rain followed by either dead calm or a fast, intense wind shift. Many tornadoes are wrapped in heavy precipitation and can't be seen; Day or night - Loud, continuous roar or rumble, which doesn't fade in a few seconds like thunder; Night - Small, bright, blue-green to white flashes at ground level near a thunderstorm (as opposed to silvery lightning up in the clouds). These mean power lines are being snapped by very strong wind, maybe a tornado; Night - Persistent lowering from the cloud base, illuminated or silhouetted by lightning -- especially if it is on the ground or there is a blue-green-white power flash underneath.
And lastly, have a family tornado plan in place. Flying debris are an added danger along tornadoes. When a tornado watch is issued, think about the drill and check to make sure all your safety supplies are handy. Or immediately check your storm cellar if you have available supplies down there.
DURING THE TONADO…
Forget about the old notion of opening windows to equalize pressure; the tornado will blast open the windows for you!
The safest place to be during a tornado is underground. If there's hurricane safe room in your home, a small room in the middle of house -- like a bathroom or a closet -- is best. The more walls between you and the outside the better.
AFTER THE TORNADO…
Keep your family together and wait for emergency personnel to arrive. Carefully render aid to those who are injured. Stay away from power lines and puddles with wires in them; they may still be carrying electricity! Watch your step to avoid broken glass, nails, and other sharp objects. Stay out of any heavily damaged houses or buildings; they could collapse at any time. Do not use matches or lighters, in case of leaking natural gas pipes or fuel tanks nearby. Remain calm and alert, and listen for information and instructions from emergency crews or local officials.
They sought shelter but the sea took them
The skipper who lost his life when his fishing boat ran aground in treacherous seas yesterday was an experienced seaman who had lived through many violent storms.
Eric Barratt, managing director of Sanford, which owned the stranded San Cuvier, told the Herald last night the man and his crew had attempted to launch the liferaft at Haurere Pt near Opotiki when it became clear the boat would run aground.
The two men who died have not been named, nor have the two crew members who survived.
A minute's silence was held at the fish market in Auckland this morning to mark the deaths.
A 16-year-old from Auckland was in a stable condition in the surgical unit of Whakatane Hospital yesterday and a second man, also from Auckland, was treated for hypothermia and discharged.
Their two colleagues were among four people thought to have lost their lives in weather-related incidents over the weekend.
James Moore, 33, died when his outrigger canoe hit rough waters off Mt Maunganui on Saturday afternoon.
He had left Maketu with three friends and went missing in the rough seas. His body was recovered yesterday.
The fourth storm victim is a 38-year-old man who died in a house fire at Meremere in the Waikato which is believed to have been started by a candle after a power cut.
The crew of the San Cuvier had managed to set off a distress beacon at 3.30am yesterday from their location 11km east of Opotiki, but did not have time for a mayday call.
The survivors were picked up by helicopter about three hours later. The body of one of the men was recovered but the second was swept out to sea. A second attempt to recover his body is to be made this morning.
Mr Barratt said the San Cuvier was normally based in Auckland but was making trips from Tauranga. The ill-fated voyage was to have lasted four or five days, he said.
He did not know what had happened to cause the boat to run aground and wasn't sure if weather warnings had been received. There would be an investigation.
"We had several vessels out and once the storm warning came, they got to shelter. We fish all through the year and when storms come along, the vessels take shelter," said Mr Barratt.
Eyewitness Margaret Thompson, who lives at Haurere Pt, told the Herald the men were trying to take their boat out again after coming ashore to shelter from the storm.
Two of the four were rescued from rocks nearly three hours after setting off the distress beacon.
She had invited one of the survivors into her home to "keep warm by the fire and have a hot drink while he waited" for the helicopter to finish searching.
Maritime NZ spokeswoman Shona Brown said emergency services initially had some trouble tracking the emergency beacon from the vessel.
"The boat was under some rocks and the satellite system may have found it difficult to find it because of that."
A fixed-wing plane found the boat shortly after heading into the air about 5.50am, and the helicopter arrived about 6.30am.