From: Hal Finney (hal@finney.org)
Date: Sun May 18 2003 - 19:14:41 MDT
I did some googling to learn more about the increase
in tornados, and found this article from Science News,
http://www.sciencenews.org/20020511/bob9.asp. In my experience they
are generally a good, objective magazine.
Meteorologists have reliable, comprehensive statistics only for
tornadoes during the past 50 years or so, says Joseph T. Schaefer,
a meteorologist at the National Weather Service's Storm Prediction
Center in Norman, Okla. The number of twisters reported from year to
year is highly variable. Over the decades, however, the average number
has been increasing by a dozen or so each year. In the 1960s, there
were about 650 twisters reported annually. In the 1990s, the average
was more than 1,100. Schaefer discussed this finding at the annual
meeting of the American Meteorological Society in Orlando last January.
What's causing the proliferation? "It's probably not climate change,"
says Schaefer. "It's people change."
As people move out of cities and disperse over larger areas, they are
more likely to spot tornadoes. As increasing media coverage makes
travelers and residents of suburbs and exurbs more weather-aware,
they are more likely to report twisters. The growing popularity of
cellular phones, which enable people on the road or in areas of downed
phone lines to call in sightings to emergency centers, will probably
continue to fuel the apparent increase, Schaefer speculates.
Now, this is just one man's opinion, but he is apparently a well qualified
expert with the National Weather Service.
I found some tornado statistics at the NOAA web site. The 2000-2003 data
is at http://www.spc.noaa.gov/climo/torn/monthlytornstats.html,
with stats back to the 1950s available at
http://www.spc.noaa.gov/archive/tornadoes/ustdbmy.html. Interestingly,
although there is an increasing trend as mentioned above, and the first
ten days of May, 2003 were the worst for tornados in decades, 2002 was
actually quite a low year, the lowest since 1988. There is considerable
fluctuation in the numbers, but last year was quite unusual considering
the trend.
Anyway, I know it's much more fun to go back and argue about who said
what, and on whom the burden of proof currently lies. Let me know when
you get that figured out - I can't wait!
Hal
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