The strong EF2 tornado that smashed through downtown Atlanta at 9:40 pm Friday night is a reminder that the U.S. is potentially vulnerable to a very high death toll from a violent tornado hitting a major city. Friday's tornado, with a width of 200 yards, path length of 6 miles, and winds up to 130 mph, was strong enough to cause an estimated $150-$200 million in damage to downtown Atlanta. Only 16 tornadoes during the 20th century caused inflation-adjusted damage more than $200 million (Brooks and Doswell, 2000), so the Atlanta tornado is one of the most damaging of all time. Fortunately, no one was killed, although at least 27 people were injured, one seriously.
As unlucky as Atlanta was to have its first tornado ever to hit the downtown area, the city was extremely fortunate that the tornado was not not stronger. What would have happened if a clone of the strongest tornado on record--the May 3, 1999 Bridgecreek-Moore F5 tornado--had hit Atlanta? According to tornado researcher Josh Wurman of the Center for Severe Weather Research in Boulder and three co-authors in a paper published in the January 2007 issue of the Bulletin of the American Meteorological Society, the toll would have been staggering--14,900 deaths and tens of billions in damage. I discussed their findings in an April 2007 blog.
However, three tornado researchers, led by Harold Brooks of the National Severe Storms Laboratory, challenged these numbers in a January 2008 article in the Bulletin of the American Meteorological Society. They argued that Wurman et al. overestimated the potential deaths from such a storm by a factor of 100, and a death toll nearer to 150 would be more reasonable. They stated:
Given that the highest death toll in a tornado in U.S. history is 695 in the Tri-State tornado of 1925, and that the last death toll of greater than 100 was in 1953, the validity of these estimates is of some concern.
The authors conceded that a violent tornado traveling the length of a rush hour-packed freeway or hitting a sports stadium filled with spectators could generate much higher death tolls. Wurman et al. responded to the criticism by defending their death toll estimates:
We acknowledge that historical tornadoes have not caused the level of fatalities estimated in our paper. However, considering that tornadoes are relatively rare and that dense population in urban and suburban neighborhoods in the United States is a relatively recent but growing phenomenon, the historical record is too short to indicate the range of possible events.
Considering that Friday's Atlanta tornado hit the Georgia Dome stadium when it was packed with 16,000 people watching an SEC tournament basketball game, I think that both groups of researchers would agree that a death toll in the thousands was quite possible had the Atlanta tornado been an EF5.
Figure 1. Doppler winds image of the March 14, 2008, Atlanta, Georgia EF2 tornado. Note the region just northwest of the city showing blues and reds right next to each other, denoting strong winds moving both towards and away from the radar in a tight circulation. This is the signature associated with a mesocyclone--a rotating thunderstorm that commonly spawns a tornado.
More severe weather expected this week
Severe weather is expected over much of the Midwest and Southern U.S. over the next three days, in association with a strong cold front that will traverse the region. The Storm Prediction Center has placed portions of Texas, Oklahoma, Kansas, Missouri, and Arkansas under its lowest classification of potential severe weather today, "Slight Risk". The Weather Underground Severe Weather page and Tornado page are good places to go to follow this week's severe weather.
Good tornado book
For those of you interested in reading about the most violent and most damaging tornado on record, the famed 1999 Bridgecreek-Moore tornado, I recommend a reading of Nancy Mathis' book Storm Warning, which is now out in paperback. I reviewed the book in a blog last year.
Annual WeatherDance contest ready for registration!
Armchair forecasters, now's your chance to shine! WeatherDance, based on teams in the men's and women's NCAA basketball tournaments, allows players to predict which team's city will be hotter or colder on game day in each round of the Big Dance. Beginning today, players can make their forecasts at the Weather Dance Web site at: www.weatherdance.org. The site will be updated with cities promptly after NCAA seeding announcements. First round Weather Dance selections must be entered by 11:59 p.m. EST Wednesday, March 19.
"Officially, Weather Dance began as a class project to get students involved in weather forecasting, but we kept it around because it got popular. People think they can do better forecasting than the meteorologists. Well, here's their shot!" said Perry Samson, WeatherDance creator, co-founder of the The Weather Underground, Inc., and Professor in the Department of Atmospheric, Oceanic and Space Sciences at the University of Michigan.
This is the third year for the game. Last year more than 2,000 people played. Most play merely for the thrill, but many science teachers involve their classes as part of meteorology units. The winning teacher will receive an invitation and $500 to join the Texas Tech/University of Michigan Storm Chasing team this spring for a day of tornado chasing. Other winners will receive a Weather Underground umbrella or a copy of the book "Extreme Weather," by Christopher C. Burt.
Jeff Masters
Brick Bldg that was destroyed by tornado landed on this car!
The first recorded tornado hit downtown Atlanta last night causing major damage
This is some of the hail after tornadoes swept through our area today.
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here is the map
Link
There is some pics of the mess coming in the WU photo gallery.
So does anyone have access to the Journal of Coastal Research? Or run across a better written article which at least names the authors or the paper's title?
Sweet Spring has arrived..Ahhhhhhhhh!
weather 456 - where did you get that infor regarding St Kitts? Is this considered odd weather to cause such waves?\
I live there. Also its not odd during this time of the year but these waves are huge. Really some of highest since our last near hit by Lenny.
This might be a stupid question for all but, does anyone think the National Weather Service issues alot more Tornado Warnings that may not merit a warning. Has technology got so good that maybe a third level of alert is needed between a watch and a warning. Just an observation. But, i too would rather be safe than sorry.
The new dual pole radars will hopefully offer some improvement. The researchers will be able to get a lot more information from the hydrometeors and make better correlations to when nados form. Is it going to vastly improve the detection of real vs maybe nados? I think that is yet to be determined. It will greatly improve rain-rate, hail size, and precip type. detection.
In the next 5 years all of the WSR-88 radars are scheduled to be replaced by the new dual-pole ones.
See details about them at: Link
As for a 3rd level of warning...I doubt the general public would be able to digest that without some confusion and confusion in this business could lead to very undesirable results.
We really need to do something about this and right now! This is so horrible that the trees are not conforming to traditionally scheduled festival weeks. Every one needs to completely give up all energy use unless it is a non-emitter so the birds do not come back 2 weeks earlier than they did during the last cooler cycle in the multi-decadal...WAIT! What?
20 - 30 years ago the trees bloomed later...SO? This is "proof" that energy facism is needed? Sure a few delicate species are in the wrong locations and might not adapt...right...how did those species come to exist anyway? Oh yeah, they are nothing more than mutations of another species, but more suited to their environment.
Hmmm. OK. So what is the problem, again? (Love the AP stories about the horrible effects of GW...always looking for that item to strike fear in our hearts, like trees and birds...snicker;)
Today is the official start of the spring season. The vernal equinox began 0548 UTC or 0148 EDT/AST this morning and will end on June 20 at 2359 UTC or 1959 EDT/AST.
....SYNOPSIS....
GULF OF MEXICO/NORTHWEST ATLANTIC OCEAN WEST OF 50W....
The western flank of a mid-upper ridge over the Southwest Atlantic is maintaining pronounce southwesterly winds aloft over the Gulf Region. A surface cold front is embedded under this southwesterly flow of moisture from extreme southeastern Mexico at 17N/95W across the Yucatan, the Southeastern Gulf and The Florida Peninsula, before entering the Atlantic. Visible imagery showed a swath of multilayer cloudiness and showers within 120 nmi behind the leading edge frontal ropes clouds north of 22N. A much broader zone of cloudiness and showers lies across the Yucatan Peninsula, and Northern Central America, partly due to enhanced lift along the terrain.
Meanwhile, the associated high pressure ridge has build across the Southern United States, Mainland Mexico, and into the Gulf behind the front. This high is producing exceptionally fair skies across the area, 20 knots of offshore flow and 7-10 ft northwest swells over open waters behind the front.
A very deep layer ridge extending from a 1023 mb high at the surface to a 200 mb ridge in the upper levels. A cold front continues from the Central Florida Peninsula and surges northeastward along the coastal waters of the Eastern United States. The front more or less surges around the flow of the ridge. Dry air is noted elsewhere near the heart of the ridge with light surface winds and scattered stratocumulus clouds. The pressure gradient between this ridge and a large low pressure area in the far North Atlantic is generating 20-30 knot winds and extremely large open ocean swells of 22 ft which are impacting the Northern Caribbean. See Caribbean heading.
CENTRAL AMERICA AND THE CARIBBEAN REGION....
A broad zone of broken to overcast cloudiness and showers are seen along Central America from 87W to 92W north of 15N. This activity is associated with a surface cold front. Weak upper ridging and dry air is seen across the remainder of the Caribbean, hindering much vertical development of cloudiness with only broken and dusty stratocumulus clouds embedded within the surface flow. A moderate high pressure system is maintaining a somewhat tight pressure gradient across the North Central Atlantic which is producing large open ocean waves. These waves are being directed towards the Northeast Caribbean in the form of 16-20 ft swells. Because of this, marine conditions remain hazardous, and swimmers and small craft should avoid these waters in the meantime. Additionally, structural damages to ports and piers are possible. These swells are less significant within the Caribbean Sea where 8-9 ft seas everywhere and near 13 ft along the Colombian Coast/SW Caribbean Sea.
by W456
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