WCCO was still using that trademark "klaxon" sound to signal tornado warnings on the air well into the 1980s, and possibly later. It's one of the station's trademarks. Late '70s/early '80s news director Curtis Beckmann said they purposely made it an awful, grating, loud sound in order to alert drowsy listeners. I believe they use an updated version of the klaxon today which sounds like an annoying noise your computer might make. It's also worth mentioning that was almost a month after the Palm Sunday tornado outbreak that devastated Indiana, Ohio and Michigan, which, while it didn't affect "CCO-Land," likely heightened listeners' awareness as to the possibilities of severe weather.
Of course, when discussing a topic like this one can't help but mention the magnificent job WCCO's neighbor 10 kilocycles away, WHAS in Louisville, did during the tornado outbreak of April 3, 1974. An extensive sampling of that coverage is posted on LKYRadio.com. The Super Outbreak was one of the worst tornado outbreaks in American history and Kentuckiana was right in the heart of it - I think something like 90 of the 300-something fatalities were in Kentucky alone (and roughly a third of those were from one tornado which destroyed the Ohio River town of Brandenburg). Louisville itself was ground zero for one of the outbreak's most damaging twisters, but the death toll in the immediate Louisville area (compared to Brandenburg which had no warning) was miraculously low, and much of that is due to WHAS' reporting (and particularly the late Dick Gilbert, the station's helicopter traffic reporter). Like WCCO, they basically cancelled their regular programming and stayed on the air with continuous news, information, weather reports and listeners' calls well into the early morning of the 4th, and even after it was all over it was some time before programming really "returned to normal." As the outbreak devastated such a wide area and tornadoes had knocked local radio and TV stations off the air in many communities, WHAS (thanks to its generator, which allowed it to stay on air after the electrical power had failed - at one point in the aircheck they even leave the air for a few seconds once the power comes back on, so they can get off the generator and back on the grid) was a lifeline for likely thousands of listeners across Kentucky and beyond that terrible day. At another point in the airchecks posted they give emergency information for Frankfort, whose primary local station was off the air. Fascinating, and chilling to listen to.
