homes in pieces and floating away, and train tracks left with nothing left to support them. the dam on the verge of failing. is it about to get worse before it gets better? our team live in the flood zone tonight. also, 70 million remain under heat advisories, from california to south florida. we ll show you what it s like living and working in triple-digit heat. so how long will it last? al roker standing by. plus, the slow-moving disaster near los angeles. a landslide taking a dozen homes and threatening even more. what s behind it. overseas, ukraine s president zelenskyy coming face-to-face with nato leaders, demanding his war-torn country be admitted to the alliance. this as he s about to meet with president biden. golf under fire. pga tour officials face intense criticism from congress over plans to merge with the saudi-backed golf tour. 9/11 families at the hearing. the growing malaria scare. mosquitos carrying the infectious disease, detected in the u.s. for