Meteorologists have come a long way in the last several decades being able to provide warnings to the public about severe weather. Doppler radar allows us to detect many tornadoes before they form. On May 22, 2011 the tornado that hit Joplin was warned and the warnings went out as they should have. Still, 159 people died in the tornado making it one of the deadliest in U.S. history. The 1953 Flint, MI tornado was the last tornado to kill at least 100 (that tornado occurred the day before the Worcester, MA tornado that nearly killed 100 as well).
What went wrong? Today the National Weather Service issued their long awaited Service Assessment of the event. One of the biggest problems cited in the service assessment is warning fatigue. Many people heard there was a warning but failed to take action because so many tornado warnings in Joplin didn’t produce a tornado in the city.
The biggest problem with the current warning system is that there is no way to distinguish between a storm that may produce a weak or isolated tornado and a long-track violent tornado that has been on the ground for miles. The current tornado warning program is black and white. Joplin, Tuscaloosa, and Springfield all get lumped in to the same pile as a tornado that sheared the tops off a few trees in someone’s backyard. When there was clear evidence that the Joplin, Tuscaloosa, and Springfield tornadoes were significant or violent tornadoes producing widespread a life-threatening damage there has got to be a better way to differentiate the threat!
Here are some of the findings from the Service Assessment:
- Finding #2c Familiarity with severe weather and the perceived frequency of siren activation not only reflect normalization of threat and/or desensitization to sirens and warnings, but they also establish that initial siren activation has lost a degree of credibility for many residents. Credibility is considered to be one of the most valued characteristics for effective risk communication.
- Finding #2d The majority of surveyed Joplin residents did not take protective action until receiving and processing credible confirmation of the threat- and its magnitude- from a non- routine trigger.
The NWS seems ready to embrace something I’ve been talking about for years. While maintaining part of the existing warning system there needs to be a second tier or warnings for truly extraordinary and life threatening situations. In the last few years the NWS has begun to use the phrase “tornado emergency” to describe strong or violent tornadoes that have either been confirmed on the ground or confirmed by doppler radar (through presence of a debris balls or other means).
There’s no doubt that many people experience warning fatigue when it comes to severe thunderstorm and tornado warnings. A lot of people don’t understand that severe weather can occur in a very isolated area while the area warned is much larger. There has got to be a better way to separate storms that may produce isolated damaging wind gusts or a small, isolated tornado and storms that pose a serious and widespread risk to life.
The tornado in Massachusetts this year is a good example of a tornado that was an extraordinary event that would be a candidate for a higher level of warning such as a tornado emergency. Unfortunately the Massachusetts tornado was on the ground, inexplicably, for nearly 12 minutes without a tornado warning in effect though there was clear radar evidence that a tornado was likely. In fact the tornado warning that was put in effect after the touchdown was allowed to expire while the tornado was still on the ground! Though there was a serious breakdown in the National Weather Service operations that day for the most part the NWS does a phenomenal job issuing warnings and communicating with the media. Though the Massachusetts case was one of the rare failures the Joplin tornado was an example of a warning issued 17 minutes of lead time prior to the touchdown. Still, even with significant lead time, there has to be a way to reduce the number of fatalities from an event like the Joplin tornado.
Assuming we’re in a perfect world and all tornadoes are detected it is important that we come up with a system to separate the most serious events from events that are more run-of-the-mill. It seems like based on today’s service assessment that may be down the road.