Now Playing: Henri continues to churn across Northeast after weakening to tropical storm
Now Playing: 22 dead, dozens missing in Tennessee flooding
Now Playing: Find out the latest on Tropical Storm Henri
Now Playing: Don Everly dead at 84
Now Playing: FDA expected to give Pfizer vaccine full approval
Now Playing: Biden under increasing fire over Afghanistan crisis
Now Playing: Race to evacuate Kabul intensifies
Now Playing: Dozens missing in deadly floods in Tennessee
Now Playing: 40 million people in Tropical Storm Henri danger zone
Now Playing: Biden promises rapid storm response
Now Playing: Off-duty cop fatally shot in Houston restaurant
Now Playing: ‘I was wrong’ to boost U.S. troops to build Afghan army: Fmr. Joint Chiefs chair
Now Playing: President Biden ‘isn’t taking responsibility’ for Afghanistan chaos: Terry Moran
Now Playing: After he stepped down as host, ‘Jeopardy!’ will reportedly air Mike Richards episodes
Now Playing: Why dollar-themed stores are booming
Now Playing: The Food and Drug Administration is reportedly aiming to fully approve Pfizer vaccine
Now Playing: Officials warn of full ICUs, nursing shortages as CDC has new warning about cruises
