"No question that we have made many important strides in securing our country from terrorism since 9/11," Napolitano said. "But the threat continues to evolve, and in some ways, the threat today may be at its most heightened state since the attacks nearly 10 years ago."
The new alert system is designed for a new era in the war on terror. And here's how it works. According to the government's plan, there are two levels. The higher is called "imminent," meaning there is a credible, specific and impending terrorist threat or an ongoing attack against the U.S.
The alert would expire after no more than seven days. However, it could be extended.
The lower level is called "elevated." The alert would warn of credible threats, but likely not specify timing or targets. But, it could reveal terrorist trends that officials believe should be shared to help prevent an attack.
It would expire after no more than 30 days and also could be extended.
The new system is expected to be in place by April 27, replacing the old color-coded one that critics blasted for being far too vague.
One indication that the old system needed to be updated is that the color-coded system had not been adjusted in more than five years.