I went to the article, looking for a legend and perhaps a time-lapse as far as this coastal inundation graphic, hoping to see some explanation as to the color coding. I assume it's wave height along the coastline, but then you've got the whitish areas going halfway up the Mississippi Valley, hundreds of miles inland. There has to be an elevation component to it, looking at the "islands" in TX, TN, MS, AL, GA and SC.
Play the QuickTime animations. Press the "pause" button when the legend pops up. Then memorize the color codings when you watch the animation. I think the highest waves (orage) were 65 meters high (200 ft).