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Deadly Tornado Hits LaPlata, Md.
With Dewey Walston
Meteorologist, NOAA
Monday, April 29, 2002; 3 p.m. EST

"A deadly and devastating tornado roared across Southern Maryland last night, killing at least three people, demolishing stores and houses and littering streets with overturned cars, torn power lines and fallen trees.

A man was killed in La Plata, the seat of Charles County, and a woman was killed in Prince Frederick, the seat of Calvert County, according to the Maryland Emergency Management Agency. This morning, the death of a third person was confirmed, according to a Charles County spokesman and police officials. The person was found in a car at the intersections of Routes 6 and 301, said the spokesman, who could not say if the person was a man or a woman. More than 90 people were treated for injuries at area hospitals." Read the full story Deadly Tornado Hits Southern Maryland (Post, April 29)."

Meteorologist Dewey Walston of the National Oceanic and Atmospheric Administration (NOAA) discusses the deadly tornado that hit southern Maryland.

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Fairfax, Va.: I have a 1.5 story Cape Cod. What's the safest place in my house to go to in the event of a tornado warning, and what are the precautions to take?

Dewey Walston: The safest place to be in a tornado is in the basement.
If no basement is available, go to an interior closet or
bathroom and cover your head.

Springdale, Va.: Describe "microburst" and what level was the LaPlata tornado.

Dewey Walston: A microburst is an intense wind that drops out of the
base of a thunderstorm and hits the surface. The La Plata damage was the result of what is now ranked as an F4 tornado with winds estimated of 250 mph.

Mount Rainier, Md.: What is the safest plan if caught in your car during a tornado?

Dewey Walston: Never try to outrun a tornado in your car. Abandon the
car and find sturdy shelter. If you can't find shelter,
get in a ditch or ravine.

A car is a very dangerous place to be.

Silver Spring, Md.: How should my family prepare for safety from a tornado?

Dewey Walston: Buy a NOAA weather radio. That is the best means of recieving weather data.

Mount Rainier, Md.: Is the a trend in the atmosphere causing more violent tornadoes in the east coast?

Dewey Walston: spring and autumn are the times of year in which tornadoes are most likely to occur in the Mid Atlantic states. That is when you have the ingredients for tornadoes which includes instability, a strong jet stream, and the clash of warm and cold air masses. There is no evidence that the rate of tornadoes is increasing each year.

Falls Church, Va.: Mr. Walston, What was the role of Skywarn yesterday in NWS's call for the tornado warnings?

Dewey Walston: SKYWARN was very valuable yesterday. We were able to see indications of the tornadoes on radar, but nothing beats a confirmed report from a human.

College Park, Md.: Has Maryland always been so prone to tornados (i.e. this most recent one and the College Park tornado in Sept.) or is this something new? Should we expect more in the near future? What is causing Maryland to turn into Tornado Alley?
Thanks!

Dewey Walston: There are no indications that the number of tornadoes is increasing. Thanks to doppler radar and weather spotters,
we are likely seeing and tracking more tornadoes than ever before.

Mount Rainier, Md.: Was the same storm responsible for all the damage in the US yesterday? Is that a record weather day?

Dewey Walston: The storm that produced tornadoes in the Ohio Valley and Tennessee Valley two days ago was the same system that produced tornadoes in our area yesterday.

Silver Spring, Md.: Hi, Dewey. Glad to see you're answering our questions. I noticed on the ETA Meteogram (a 48-hour forecast of how conditions are expected to change in a cross-section of the atmosphere over a given region), which was issued late Saturday evening showing expected conditions for the next two days, that the "timeline" was showing the lower levels of the atmosphere warming yesterday afternoon through early evening while, simultaneously, the upper levels of the atmosphere were cooling. How often have you observed this happen in the MD/DC/VA area and how would you correlate this with yesterday's severe weather outbreak?

Dewey Walston: We observe these conditions frequently. However, there are many more things we look at to determine the threat of severe weather. For example, we look at the strength of the winds aloft and the amount of shear in the winds aloft. We also look for dynamic support for convection.

Yesterday, all the ingredients were present for severe weather.

Manassas, Va.: Which is more serious--a tornado watch, or a tornado warning?

Dewey Walston: A tornado watch means conditions are favorable for tornadoes. It does not mean that tornadoes will occur. It only means they are possible.

A tornado warning means that tornadoes have been indicated by radar or spotted and is heading toward the warned counties. When a warning is issued, TAKE COVER!!

Herndon, Va.: I was born and raised in Nebraska, so tornados and tornado warnings were just a part of growing up. How much more likely is someone in "tornado alley" to be close to a tornado than someone in the D.C. area?

Dewey Walston: Tornadoes are more likely to occur in "tornado alley" than in our area. However, as we have seen, this area is not
immune from tornadoes.

McLean, Va.: What is the best way to escape from a tornado? For example, the people who left KFC - I'm not sure I'd think I would be safer in the parking lot? If you're in a house with no basement, are you safer going outside? Where do you stay outside? Are you safer staying in your car if you see it while you're driving?

Dewey Walston: If you are in a house with no basement, go to an interior
closet or bathroom away from windows and outside walls.

If you are outside, seek sturdy shelter. If you can't find any, then get in a ditch or ravine and cover your head.

Get out of your car!! Its a very bad place to be. Cars can be tossed around like toys. If you are in your car, get out and get into a sturdy structure. If you can not find one, get into a ditch or ravine. JUST GET OUT OF THE CAR!

Daleville, Va.: According to the Washington Post article, it reports that this tornado was an F4. How is a tornado rated?

washingtonpost.com: Deadly Tornado Hits Southern Maryland (Post, April 29)

Dewey Walston: A tornado is rated on the fujita scale from F0 to F5. The strength is determined by going and looking at the damage and estimating wind speeds based on damage.

Arlington, Va.: What can I and my family do to protect ourselves from tornadoes? What can we do to get out of the tornado's way? Is there a Web site we can visit to get more information on how to remain safe during a tornado emergency?

Dewey Walston: I suggest you visit our web site at :

http://www.nws.noaa.gov/er/lwx

You can find forecasts and other interesting things including pictures of yesterday's tornadoes.

The best way to protect yourself is to buy a weather radio.
They sound an alarm when severe weather is approaching your location. They can be bought as most electronic stores such as Radio Shack.

Washington, D.C.: Does topography become a major factor for a tornado to touch down?

Dewey Walston: Topography can affect a tornadoes path and strength. However. it is a myth that tornadoes can not occur in mountains and it is a myth that tornadoes avoid big cities.

Arlington, Va.: What ranks as an F5 and how far was La Plata from an F5 ranking? Thanks!

Dewey Walston: An F5 has winds of 260 mph or greater.
The La Plata tornado has been estimated at 250 mph.

Waldorf, Md.: Mr. Walston:

The storm that produced the La Plata tornado was closely tracked throughout the day including doppler radar tracking by local news stations up until about 7:00 pm. After indications that a tornado may have been spotted near Manassas Virginia around 6:30, no further doppler radar returns indicated a tornado and the tornado watch for Southern Maryland and other Metro areas remained in effect until 7:45. At about 7:00 pm local news stations returned to network broadcasts and the tornado watch remained an as inset on our TV sets. The La Plata tornado touchdown occurred at approximately 7:10. Was its development caught on doppler radar or was a visual sighting used to issue the warning? Also, will the doppler radar data be used to help classify the tornado's strength.

Dewey Walston: A tornado warning was issued for Charles county based on doppler radar imagery. However, within a minute of the warning being transmitted, we got confirmation from spotters. The dopper radar imagery was some of the most amazing imagery I have seen. It looked like something you would see in the plain states.

Bladensburg, Md.: Has it been determined what category the storm actually was?

Dewey Walston: F 4 with winds of 250 mph

Waldorf, Md.: We live approx. 5 miles NE of LaPlata. During yesterday's storm, we experienced an onset of small hail pellets that, over the course of a few minutes, increased in size. Before the storm had subsided the hail pellets were the size of tangerines. What causes the change in hail size and how does it relate to the tornado?

Dewey Walston: Hail size is based on the strength of the updrafts and downdrafts of the storm. The stronger the updrafts and downdrafts, the larger the hail.

Washington, D.C.: What's the difference between a twister and a tornado? I heard the two terms used in last night's weather reports. Are they are same?

Dewey Walston: They are the same.

Fairfax, Va.: I know it is very early, but do you have any feeling that this type of weather is the result of global warming? I thought they said one of the effects of global warming was more severe weather.

Dewey Walston: You can't make a determination about global warming based on the fact that we have had two severe tornadoes in the past several months. We may go several years without severe tornadoes.

Bethesda, Md.: I'm relatively new to the area, but in the 8 months I have been in DC there have been 2 killer tornados (College Park last fall, and yesterday). I wasn't expecting to move into a mid-atlantic tornado alley. Is this very common in the area or are these just freak occurences?

Dewey Walston: Its just "bad luck" that we have had two large tornadoes in such a short period of time. The atmospheric conditions just so happen to come together last September and yesterday which favored tornadoes.

Tornadoes are not uncommon to this area, but we do not see as many tornadoes as they do in the midwest and plain states.

Mount Rainier, Md.: Do more tornados occur about certain times of year? What weather conditions create a tornado?

Dewey Walston: Here in this area, we see a peak in tornado activity in the spring with a smaller peak in the autumn. You need a strong jet stream, instability and the clash of warm and cold air masses to create the conditions necessary for tornadoes and this occurs mostly in the spring and autumn.

Greenbelt, Md.: The national weather service issues tornado warnings on the basis of doppler radar indicated mesocyclones or tornado signatures. Doppler radar detection works on the princpal of objects moving in diffent directions in two dimensions. With one weather service radar, is it possible that certain locations in your area of responsiblity may be 'blinded' by a storm moving in such a way as to reduce or even eliminate the radar velocity estimates?

Dewey Walston: We not only have access to our own redar, but we have access to all surrounding radars as well. So if there is something on our radar that we do not see that well, all we have to do is look at one of the surrounding radars. Radars are in Pittsburgh, State College, Dover, Wakefield VA, Blacksburg VA and Charleston WV

Prince Frederick, Md.: I was not even aware of a tornado until I heard it on the news this morning. We did get very heavy rain with hail for about 20 minutes. In fact, the rain pelted straight down -- the wind was completely still. Is this a normal occurrence for areas outside the tornado's path?

Dewey Walston: A tornado is a very small event when you consider the large scale of the atmosphere. Its common to hear reports such as yours.

Arlington, Va.: When was the last time an F4 struck this area, and has an F5 ever been recorded in Maryland or Virginia?

Dewey Walston: To my knowledge, we have never had an F5 in Maryland, DC
or Virginia. The La Plata tornado is as close as we have gotten and it wouldn't bother me a bit if we never had an F5.

F4's and F5's do most of the killing in this country.

Fells Point, Md.: I was watching the local DC news when the storms hit. I could not hear what they were saying, but I was able to see the radar images (who knew it went all the way to purple ?!?!)

The image on channel 9 had several small, superimposed circles rotating over the map. Were those actual tornados or did the computer cite those areas as having a high potential for one?

Dewey Walston: I believe those circles were likely the radar indicating that there was a circulation or mesocyclone. In other words, the radar found a circulation there which could lead to a tornado.

Port St. Lucie, Fla.: Has a tornado ever hit Washington, D.C.?

Dewey Walston: There have been documented tornadoes in the district. One
F3 and several F1s and F2s.

Seattle, Wash.: Why are tornados more prevalent on the East Coast and Mid West than the West Coast. I am in Seattle and have never experienced a tornado. Why is that?

Dewey Walston: The Pacific ocean keeps Seattle quite stable much of the year and storms generally move west to east across the Seattle area. With this storm track, weather usually comes off the Pacific which usually means stable conditions.

Orlando, Fla.: How many tornados total were confirmed yesterday in the mid atlantic? Thank you.

Dewey Walston: There were at least 3 in our service area. Two of which were twins. You can see the images on our web page at:

http://www.nws.noaa.gov/er/lwx

Washington, DC: One of the pictures on the Web site you mentioned earlier shows a "twin twister" yesterday in Calvert County. So were there actually two tornadoes? Which one was the F4?

Dewey Walston: Based on the picture on the internet, its tough to tell which one was the F4. They both look pretty intense.

Fairfax, Va.: Is there an estimate of the maximum Fujita scale strength of the tornado? The damage visible on television seems to indicate a strong intensity along parts of the track. Also, was there a touchdown in Prince William County, VA, or only a funnel cloud sighting?

Dewey Walston: F4. 250 MPH. Radar indicated some rotation over Prine Williakm county but we got no confirmed reports of tornadoes on the ground.

Dewey Walston: Well gotta run.

By the way, the tornado in La Plata has just been upgraded
to F5 class. Wow....

Its been nice chatting with you.

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