The U.S. Department of Homeland Security unveiled its new terror alert system on Wednesday. It will go into effect next week.
Homeland Security officials have done away with the old color-coded system, replacing it with one that has only two alert levels -- elevated and imminent.
An imminent threat would be the highest alert. Because it would only be issued if an attack is about to happen or is ongoing, it would expire seven days after being given. The elevated warning would expire 30 days after being issued.
The new warnings could be conveyed to the public through Facebook and Twitter.
Officials said the old system, which described the threat in five colors, was too vague.
"The major problem with the color-coded system is it didn't convey information. Having a system that sunset is a major improvement," Homeland Security Secretary Janet Napolitano said.
Napolitano says the threat picture in the U.S. is currently at an "elevated baseline," and future public warnings will hinge on specific and credible intelligence above and beyond that threshold.
She says the terror threat to the U.S. is at its highest since 9/11 because of the increasing number and types of international and homegrown threats. This does not mean there is a specific threat of an imminent attack.