Weather Service Hopes New Warnings Will Scare You
Apr 05, 2012
Admit it – you're guilty. Yes you. And so am I.
We're guilty of ignoring weather warnings; whether (no pun intended) it be a severe thunderstorm warning, flash flood warning, or tornado warning. We've all done it; either ignored it completely or stuck our heads outside to get a glimpse of Momma Nature at her worst.
|This week tornadoes ravaged parts of Texas, including the Dallas-Fort Worth area. Luckily, no one died as a result of the storms. The National Weather Service hopes a new format to its warning system will continue to reduce or eliminate fatalities in storms. Photo credit: Parrish Velasco/ASSOCIATED PRESS.
And who can blame you? Some estimates say the National Weather Service has a failure rate of as much as 75% when it comes to issuing a tornado warning for populations that are not impacted during that event. It's hardly their fault – it's the nature of the beast; so to
Not too long ago, a tornado warning was issued for an entire county or parish, but only one storm may have been present, affecting a small fraction of the geographic area of the warning. Recently, warnings became more geographically focused, thanks to better forecasting technology. But, the warnings were still too broad.
Now if you look at the other side of the issue, the National Weather Service is actually doing a pretty good job. In 2011, nearly every major tornado that occurred in the US had a warning issued either shortly after it was spotted or detected on radar or prior to its actual formation. In other words – every tornado had a warning precede it.
Officially, the National Weather Service says it's success rate for warning violent tornadoes (EF3-EF5) is about 94%, with an average 18 minute lead time. Weaker tornadoes are more difficult to predict and usually short-lived, dropping the success rate to 68% with an average 12 minute lead time.
But that's not good enough. People are failing to heed the warnings and as a result are injured or killed.
As a result, the National Weather Service has proposed a stark new method of warning about the likelihood of severe thunderstorms and tornadoes.
The new warnings, called impact based warnings, are being tested at five National Weather Service forecast offices in Missouri and Kansas. The new warnings will focus more on the severity of the storm's expected impact and are designed to scare you into hiding.
|Raw video of a tornado sweeping through a tractor trailer terminal in Texas earlier this week. (Forgive the audio - its best to mute it).
The test phase, which began April 2, will use three tiers of warnings for tornadoes and two for severe thunderstorms. Each warning will be issued based on the expected impact of the storm and will contain wording such as “complete destruction...likely”, “mass devastation” and “unsurvivable.”
Under the old system, a weak tornado and a powerful EF-5 tornado would have been warned with very similar language, making it difficult for the public to understand how dangerous the situation was.
Once complete, a firm in North Carolina will analyze the results of the test and recommend whether the new format will be expanded to other areas across the country.
While I applaud the National Weather Service for taking steps to combat complacency among the population, I fear that the wording of warnings is not the entire issue. Unless you can broadcast that warning in an audible format so people can hear the potential impact; I doubt that everyone will drop what they are doing to read the text
of the warning.
I also fear that warnings for weak storms or tornadoes will give people a false sense of hope. Similar to forecasts for weak hurricanes, some might choose to ride out the storm. The danger here, and it's been documented many times, is severe thunderstorms and
tornadoes can gain strength (or lose it) very quickly.
Because of these quick changes in strength, I fear the National Weather Service may be setting itself up for additional complacency by forecasting a devastating tornado that ends up knocking off some shingles and branches. Or worse, forecasting a weak tornado that ends up growing into a monster.
What are your thoughts on the new warnings? If you're told a storm will likely “not be survivable without adequate shelter” make you take immediate action? If you're in the Midwest and have seen the new warnings, what do you think? Please share your thoughts.
|NWS slideshow explaining the new warning system. Click on image to open. PDF format.