down down turn around having fun is what it's all about on this sunday night, flood fears. with temperatures on the rise, growing anxiety over the threat posed by mountains of snow and what happens when it starts to melt. new allegations against bill cosby from women who say they were victi izimized who worked the actor claims he paid off women. hooked. america's heroin epidemic. and we go behind the lines to find the source. and blues brothers. a legendary musician setting the stage for a young progeny. from nbc world headquarters in new york, this is "nbc nightly news" with lester holt.