Tornado Emergencies – Worthwhile?

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Velocity signature for tornado heading into West Springfield. Ironically, there was no tornado warning at this point in the storm's life.

There’s no question we’ve been desensitized to tornado warnings (see this blog post by James Spann). There are far too many warnings that turn out to be false alarms. Warnings can cover hundreds of square miles and even a large tornado would do damage over a miniscule section of the warned area. In fact at least 80 percent of warnings don’t even wind up verifying with any touchdown at all!

Part of the problem is that our technology is only so good. Extra doppler radars would cut down on the number of false alarms but there’s little chance we’ll double or triple the existing network. It seems to me, and this isn’t a criticism, that the National Weather Service tends to overwarn to cover their butts. I can’t blame them.

Given the public complacency the NWS has been issuing “tornado emergencies” within tornado warnings in rare cases where a large or violent tornado has been confirmed on the ground. The first one was issued in the May 3, 1999 Oklahoma City tornado and 82 have been issued since.

Here’s some interesting research from Patrick Marsh at OU. He found that the false alarm ratio is surprisingly high for something that is supposed to be issued only in the most extreme cases. In fact using significant tornadoes (EF2 or greater) the false alarm ratio is 46%!

So what’s the solution if tornado emergencies aren’t? How do we differentiate a run of the mill tornado warning for a storm that will be lucky if it can produce a 60 mph wind gust and a monster supercell dropping an EF3 or greater tornado in downtown Springfield? Should they all be covered by the same kind of warning?

3 thoughts on “Tornado Emergencies – Worthwhile?”

  1. Hi Ryan,

    It’s irksome to have a t.v. meteorologist tell me “to seek shelter immediately” for a possible tornado touchdown in Thomaston when i live in Southington. Probabilities vs. possibilities. Sometimes I think it is forecast imprecision, sometimes I see it as alarmist hype to maximize viewership. Liability culture+ratings competition= over-warnings. Every thunderstorm isn’t an emergency necessitating breathless urgency. I do appreciate what you folks do…

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    • John,

      I agree 100% with you. Part of it is imprecision and part of it is a lack of knowledge that some TV weather people (many aren’t even true meteorologists regardless of how they refer to themselves on air) have about severe weather. I don’t think it’s a ratings ploy – I think that’s too cynical of a view.

      For a marginal threat with a tornado warning I personally tell viewers to be ready to head to a basement or small interior room if they feel threatened. I feel comfortable enough analyzing the storm structure and radar to be able to do that while some others on TV do not and basically will just relay the NWS warning verbatim.

      Part of the problem is with the NWS overwarning and part of the problem is the media – I think both are an issue.

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