The National Weather Service’s NOAA Weather Radio system finally finds its purpose with the introduction of a piercing “warning tone” preceding emergency weather announcements such as severe weather warnings. Manufacturers of weather radio receivers (an item which hit the market in 1970) use the five-second burst of 1050Hz warning tone to trigger attention-grabbing alert sounds and then activate the radio so the relevant information can be heard. NOAA Weather Radio broadcasts on 29 stations around the country, and the agency continues to bring new transmitters online throughout the year.
