Some communities use sirens; others may use reverse 911 calls or text messages pushed out to mobile phones.
Check with your local NWS forecast office or community emergency management office to find out the best way to get a warning in a timely fashion.
Moreover, it's important to recognize that adjoining communities have different approaches to warnings; what you hear on a weekend may be different from what you hear during the week if you live and work in different communities.
In a followup study of a tornado that devastated Joplin, Mo., in May 2011, NIST researchers found that Joplin used the same siren pattern for tornadoes that it did for other wind events. And it used a different pattern than did some surrounding communities. Indeed, the researchers surveyed 75 communities across the US and found a wide variety of siren patterns used as tornado warnings. One recommendation from the study: The US needs to establish a uniform set of "clear, consistent" standards for community-based tornado warnings.
It's wise to have more than one way to receive the warnings, if possible. Thunderstorms that dropped a tornado in Woodward, Okla., in April 2012 also dropped a lightning bolt that disabled the siren-warning system for a section of the city that later was hit by the tornado.
