A tornado warning remained in effect Friday night for northwestern Livingston and southern La Salle counties until 9:45 p.m. as a severe squall line capable of producing tornadoes and damaging straight-line winds moved east across northern Illinois.
At 9:11 p.m., the line was near Grand Ridge, South Streator, Flanagan and Gridley and was traveling east at 45 mph. The warning covered 15 towns, including Streator, Pontiac, Marseilles, Seneca, Flanagan, Wenona, South Streator, Grand Ridge, Cornell, Ransom, Rutland, Kangley, Long Point, Dana and Leonore.
The warning was based on radar-indicated rotation, and the weather service said flying debris posed a danger to anyone without shelter. It warned that mobile homes could be damaged or destroyed, with roofs, windows and vehicles also at risk and tree damage likely.
Residents were urged to move to a basement or an interior room on the lowest floor of a sturdy building and stay away from windows. Those outdoors, in mobile homes or in vehicles were told to get to the closest substantial shelter and protect themselves from flying debris.
The storm threat was part of a severe thunderstorm threat for Friday in northern Illinois, and the weather service cautioned people not to wait to see or hear a tornado before taking cover. By then, the message was blunt: if you are in the warned area, move now.