KANSAS CITY, Mo. -- Tornado sirens didn't sound overnight when two tornadoes touched down in the Northland because the National Weather Service hadn't issued a tornado warning for the area.

The area was under a severe thunderstorm warning.

Andy Bailey, warning coordination meteorologist for the weather service, urged residents Friday to get weather radios and to pay attention when severe thunderstorm warnings are issued.

"The thing we want people to understand about this is the outdoor warning sirens are made for that, to warn people outdoors," Bailey said. "They are not meant to be an indoor warning, notification system. People should not rely on sirens indoors any time of the day or night. The thing people need to focus on is getting a weather radio."