oddball question

[Brian A. Schmidt]

I'm sure this has been brought up in the past but... when I was a kid way back in the mid 70's I read a safety pamphlet which told you how to detect a tornado by turning your TV to a vacant channel and turning the brightness all the way down. If a tornado was nearby, it was said, the screen would brighten or white-out. There was also a similar trick with AM radio-- you could set it to the low end of the dial 520-530khz and tell by the nature of the static if a tornado was near-- intermittent static was caused by lightning whereas a tornado caused a continuous and sustained rushing sound. Obviously, these days we have many other resources at our hands, but did anyone ever use this technique in the past ? Scientifically, what is going on here? Does a tornado cause some sort of electromagnetic interference, or emit RF-- hence being able to "tune it in" on a TV/radio? Just curious!

 

[David Wolfson]

Simple answer -- no. It's been investigated and if there were a unique, detectable tornado radio signature everyone at risk would have a special detector. And Stormtrack members would have an average of about five detectors stuffed in every vehicle, nook, and cranny! :wink:

 

[Jeff Snyder]

Well, maybe, maybe not... Check out website of the Infrasonic Network Program at NOAA's Earth System Research Laboratory --> http://www.etl.noaa.gov/programs/isnet/ ... The gist is that they are using sensors to detect very low frequency audio signatures that may be associated with strong rotation / tornadoes.

Here's a quick snippet and graphic from the website:

A 1995 observation of infrasound from an infrasonic observatory co-located with the CHILL Doppler radar in NE Colorado documented infrasound originating from the vicinity of rotation aloft, descending to the surface in the area of a tornado report. This observation led to a review of archived data, identifying over 100 cases where the directions and times of signals matched documented observations of tornadoes. Subsequent field measurements through the summer of 2002 continued to indicate that infrasound could be useful for severe weather warning.
...

I'm not at all familiar with their work, so I can't comment on this beyond mentioning that it exists.

 

[Tim Johnson]

Interesting!

I can already see a new addition to the most valuable items for chasing list...

GPS
Laptop
Camera
IPOD/Headphones with downloadable Tornado detection algorithm.

I'm telling you, apple will rule the world with that device at some point :lol: