It has been a crazy winter, filled with snow and bitter cold. Mother nature trumped the winter weather on Thursday with the first severe weather episode of 2014.
The National Weather Service issued five tornado alerts. Only three weak funnels appeared -three out of five with a false alarm rate of 40 percent.
Why does the Tornado Warning policy treat weak, spin-up funnels the same as it does monstrous killer tornadoes? The policy is set at high levels in the National Weather Service bureaucracy.
The system needs to be fixed.
On the high end of the Enhanced Fujita Scale - the big tornadoes (EF3, EF4 and EF5) - require big thunderstorms with strong rotation. They are easy to see on Doppler Radar and easy to warn. These tornadoes are the headline grabbers and create huge nightmares.
These tornadoes make up less than 6 percent of the total number of tornadoes.
However, almost 80 percent of all tornadoes end up on the low end of the Enhanced Fujita Scale, rated as EF1 and EF0.
These are the small vortices at the front edge of a thunderstorm. The spin quickly and touch down briefly. These are hard to see on a radar and are the source of the majority of false alarms.
The damage near Osgood, Indiana last Thursday is what an EF1 or EF0 produces. The damage was mostly minor and not widespread.
However, incredibly the NWS Tornado Warning policy treats both the monstrous tornadoes and these small one the same.
Bob Ryan, former president of the American Meteorological Society, wrote:
"There are small whirls and the real McCoy tornadoes. We all have a role in effectively communicating the real danger, beyond just yelling TORNADO WARNING!"
Since 1950, no deaths have been caused by an EF0 tornado and only one has been attributed to an EF1.
This means that Tornado Warnings for EF0 and EF1 tornadoes are not saving lives because a funnel of that strength is just not deadly.
During the Doppler Radar era, since 1995, the Wilmington NWS office has issued 542 Tornado Warnings.
Based on the National False Alarm Rate of 75 percent, more than 400 of those were false alarms.
The False Alarm Rate is a glaring red flag, pointing out a potentially deadly problem.
In their peer review study, "False Alarms, Tornado Warnings and Tornado Casualties" published in 2009, Kevin Simmons and Daniel Sutter wrote:
"We have found strong evidence that a higher local, recent far [false alarm ration] significantly increases tornado fatalities and injuries."
If the NWS does not fix the false alarm problem, we may see deaths and injuries increase. Many meteorologists feel it is time to fix the false alarm problem.
Tornado Data: NOAA Storm Prediction Center: http://www.spc.noaa.gov/gis/svrgis/
Tornado Warning Data: Iowa Environmental Mesonet: http://mesonet.agron.iastate.edu/
Peer Reviewed Journal Articles:
False Alarms, Tornado Warnings, and Tornado Casualties
Kevin M. Simmons, Daniel Sutter
Weather, Climate, and Society
Volume 1, Issue 1 (October 2009) pp. 38-53
Tornado Warnings, Lead Times, and Tornado Casualties: An Empirical Investigation
Kevin M. Simmons, Daniel Sutter
Weather and Forecasting
Volume 23, Issue 2 (April 2008) pp. 246-258
Bob Ryan Quote: Storm Watch 7 Weather Blog
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