Thursday, May 26, 2011

Tornadoes through Time

Randall Stephens

I'm visiting family in the Kansas City area, on the edge of the infamous tornado alley. (I have many memories of sleeping in the basement while the dark clouds and funnels blew fiercely overhead.) The recent devastation in Alabama and Missouri reminds us of the brutal toll nature can take. My cousin's home in Joplin was obliterated by the twister. Fortunately, she was away from home. This is the worst tornado season here since the early 1950s.

The worst in American history was the "Tri-State" tornado, which ripped through Missouri, Illinois, and Indiana on March 18, 1925. It blasted a path of destruction across the region and took 695 lives.

On the day after it hit the Chicago Tribune announced "A tornado tore through southern Illinois late yesterday after lashing Missouri, and then caused considerable damage in Indiana before it died out." Radio and newspapers broadcast the details shortly after the winds died down. "In some places, where the wind struck hardest, whole buildings were moved from their foundation, a grain elevator in De Soto having been carried intact some forty feet." A schoolhouse in the same city collapsed. Only a few pupils in the packed building escaped unharmed.

Midwesterners and Americans across the country were shaken. A swift death by a storm could happen anywhere in the region, and with little warning.

In the era before accurate forecasting and warning systems, Americans had good reason to worry. The deadliest tornadoes in the nation's history could wipe out a community and leave a trail of casualties in its wake. Here's a list of those deadliest, compiled by the National Oceanic and Atmospheric Administration's (NOAA) (see the full 25 here):

Rank, Date, Region, death toll

1) 18 Mar 1925, Tri-State (MO/IL/IN), 695

2) 06 May 1840, Natchez MS, 317

3) 27 May 1896, St. Louis MO, 255

4) 05 Apr 1936, Tupelo MS, 216

5) 06 Apr 1936, Gainesville GA, 203

6) 09 Apr 1947, Woodward OK, 181

7) 24 Apr 1908, Amite LA, Purvis MS, 143

8) 22 May 2011, Joplin MO, 118 (est.)

9) 12 Jun 1899, New Richmond WI, 117

10) 8 Jun 1953, Flint MI, 116

Most of these violent twisters touched down in the heart of tornado country. But, historians might ask what factors have made certain storms at certain times and places more deadly than others. What factors have combined to cause the greatest destruction and loss of life? How have poverty and rural isolation factored in?

Technological innovation has lessened the damage and helped prepare civilians for the worst. Over at NOAA Roger Edwards provides some background to that relatively recent scientific research:

The National Severe Storms Laboratory has been the major force in tornado-related research for several decades. NSSL has been a leader in Doppler radar development, research and testing, and has run numerous field programs to study tornadoes and other severe weather since the early 1970s. Others heavily involved with tornado research include UCAR/NCAR, the University of Oklahoma, the Tornado Project, Tornado History Project, and overseas, the European Severe Storms Lab (Germany) and TORRO (UK). Members of the SELS/SPC staff have done research related to forecasting tornadoes for many years. Almost every university with an atmospheric science program, as well as many local National Weather Service offices, have also published some tornado-related studies.

One of the major advances for storm detection and tracking, of course, was Doppler radar, described by NOAA as follows:

Doppler radar can see not only the precipitation in a thunderstorm (through its ability to reflect microwave energy, or reflectivity), but motion of the precipitation along the radar beam. In other words, it can measure how fast rain or hail is moving toward or away from the radar. . . . Doppler radar and severe storms research were joined in the early 1960s when the National Severe Storms Project began in Kansas City, and continue to this day at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma. The Union City tornado in 1973 began a treasure trove of NSSL research Doppler measurements of supercells and other hazardous storms. In the 1980s, the push to get Doppler radars into warning operations became well-organized as the NEXRAD (NEXt generation weather RADar) program.

We're roughly half way through tornado season. Let's hope we've seen the worst of it. If not, let's hope early warning systems do their work.

No comments: