Nature’s Guessing Game

September 1, 2011 | By More

Winter storm warning, tornado watch, and wall cloud are familiar weather terms to most Arkansas natives. You already know what to do and where to go when you hear these warnings, maybe learned it at an early age so you wouldn’t forget. School closings in winter or hiding in a storm shelter at other times, your emotions probably jumped from joy to fear and excitement as you waited for something that may or may not have fulfilled your big expectations.

Today, when you hear the weather report and it mentions “storm warning” or “tornado watch”, you might assume you still have got time to complete another task before taking shelter. After all, the weather report specified another area of the county, or a neighboring county, and said the storm wouldn’t arrive for another hour. No problem, right?

Wrong. According to Steven F. Piltz, Meteorologist in Charge of the National Weather Service in Tulsa, Okla., people who Storm Prediction and Safety Tips from the Experts dismiss weather reports that don’t pertain to their specific local or believe they have time until the storm comes, are putting themselves at big risk.

“We (meteorologists) can only scientifically guess at the probability of a damaging storm hitting a specific area. There are so many variables to a storm’s path and velocity. We have a better idea of what is occurring 1500 feet above the surface of the land, than what is actually happening on the ground. Although the weather service is equipped with state-of-the-art technology, the human element is critical, said Piltz.

”Believe me, predicting the weather is not like playing a video game. Every time we issue a storm warning, we’re on edge. We try to do the best we can, but in the end, we can only make our best guess,” said Piltz. That’s why it is so important to get verification from “storm spotters” and other people on the ground. Amburn agreed.

“We need to get real-time feedback to hone our predictions. We are only as good as the information we get” added Steve Amburn, Science Officer for the National Weather Service.

Storms can suddenly change direction and usually turn at right angles. “We use a polygon (a shape with many angles) to project the path of the storm, with the narrow angle closest to the storm. If a storm suddenly changes direction, the new path may include areas not in the original storm warning,” said Amburn. “It is not only important to listen to weather alerts, but critical to observe the weather on the ground. Radar sweeps aloft at 14 different “tilt” elevations, but it does not operate at ground level,” said Amburn.

“Without the input of people on the ground, we can’t verify if our predictions are correct. We need that information to improve our accuracy,” Piltz said. Aptly named SKYWARN, the Franklin County Emergency Management volunteer storm chasing team provides those critical eye-witness ground reports for the Tulsa meteorologists.

Although March, April and May are usually the most active months for damaging storms, January and February have also been problematic, said Piltz. However, a bad storm can hit anytime during the year.

WINTER STORMS

National Weather Service Meteorologist, Robert Darby, said that 70% of winter storm injuries result from vehicle accidents, while 25% occur when people are caught out in the storm. Power outages can also be fatal. Some people are poisoned by carbon dioxide from using an outdoor grill or other heating device not intended for indoor use. Fires are also more common when the electricity is out. A couple of house fires in the Tulsa area overnight (Nov.30) were probably the result of power outages, said Darby. “Be extra cautious using candles to light your home,” he added.

Darby also explained the time line for issuing winter weather alerts.

“A winter storm watch is usually issued 48 to 72 hours before the storm is expected to hit. This is when people need to prepare by securing, medical supplies, prescriptions, food and water and making plans in case the electricity goes out. A freezing rain event can keep electricity out for a week in some places,” said Darby. A “winter storm warning” is issued when the storm is about to happen. This is the time to stay inside and travel only when necessary. FEMA and the Red Cross have a brochure, “Winter Storms, The Deceptive Killer” available on-line at www.fema.gov.

TORNADOS

When asked about common misperceptions regarding tornados, Piltz and Amburn agreed that opening a window is “a waste of time”. Usually, the most damage is done by winds accompanying a tornado. By the time a tornado hits and air pressure changes, most damage has already been done, they agreed. Straight- line winds and downbursts, which are responsible for most thunderstorm wind damage, can exceed 100 mph and will also do considerable damage to the inside of a structure if a window is left open.

Another area of the house that can cause major damage is the garage, as most garage doors are not made strong enough to withstand strong winds. Once a garage door has been blow open, the wind rushes upward to find an exit and often takes off the roof.

Topography also has nothing to do with the path of a tornado, said Piltz. Being in avalleyornearariveroronthesideofa hill won’t necessarily protect you, he said. “That’s just wishful thinking,” he added.

WHAT’S NEXT?

Another frequent question asked of Piltz and his colleagues is why the weather of recent years seems to be getting so much worse.

“Weather is cyclical. During 1953 and 1954, the weather patterns were very similar to the ones in the past few years with similar drought, and hurricane and tornado frequency, explained Piltz.

The best thing a person can do in a weather emergency is to be prepared and have a plan. The government offers a $1,000 rebate program for homeowners who install a storm shelter. The basic shelter costs approximately $3000 to build.

“Safe rooms” in a home are more expensive to build. Installing “hurricane clips” in exposed areas is also helpful as they can quadruple the strength of a structure. You can also purchase a “closet kit” if your home is on a slab foundation. It is also a good idea to make a sketch of where you plan to seek shelter during an emergency and notify your local fire department of the spot, in case you need to be rescued.

Fortunately, through the diligent efforts of the Skywarn team, Franklin County is one of only 12 counties in Arkansas to be awarded the “Storm Ready” designation.

Tim Gehring, Northwest Area Coordinator for the Arkansas Department of Emergency Management, said that Franklin county Emergency Management Severe Weather Officer, Rick Covert, who has put in over 300 volunteer hours this year alone, and other dedicated members of the team have made Skywarn the most active group in the state.

Other members are still needed however. Covert can be reached via e-mail at kd5gsp@hotmail.com.or visit the Office of Emergency Services at www.fcoes.com The National Weather Service web site is www.weather.gov/ tulsa or call toll-free Severe Weather Reporting (800) 722-2778.

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