Well, as I've said before, you could have "level orange" alert, followed by "level-orange-going-a-bit-red" followed by "level-not-quite-red-but-not-so-orange-either"...
...followed by "level-okay-you-got-me-it's-red-but-with-STILL-a-bit-of-orange-in-it".
Why do we need colors at all? When the news reports 'today, the gov't raised the alert to orange - that means high state of alert.' If they have to tell you what the color means thry could just say, 'today, the gov't raised the alert toa high state of alert.'