ne>>> let the m begin.g millions racin to finish their brackets, the ncaa tournament tips off. today tuesday, march 19, 2019. >> announcer: from nbc news, this is "today" with savannah guthrie and hoda kotb live from studio 1a in rockefeller plaza. >>> welcome to yooday," thank for joining us on this tuesday morning. we'll start with the dueling disasters. th pfeiffers and floods, crews battling that massive chemical fire in houston, facing new challenges this morning. further north, millions remain threaten by historic flooding. we'll start with nbc's kathy park in omaha, nebraska. hey, kathy, good morning. >>> hoda, good morning to you.'v seen these disasters having a big impact in this behind me is the missouri river. the devastation has been widespread in themidwest. later today vice president mike pens will be in the area to take a closer look at the damage. this morning parts of the midwest still under water, devastated by historic flooding that has still not receded. >>here are still places fully submerged, no access. s people stilltuck in their homes. >> entire communities in