Transcript for Death toll rises after Irma, Texas still feels Harvey's punch
??? Stand by me ??? Tonight Hollywood's a-listers. Got together to raise money for those impacted by hurricanes Harvey and Irma. Some singing -- ??? lean on me ??? In my home town city of Houston, people need food. Others asking for donations. We don't want you to just watch. Donate what you can. Row after row of big names. Julia Roberts, George Clooney, manning the phones of the will prompted by images like these of Houston two and a half weeks ago. The talent manager decided to put together as big of an effort as possible to help Texas. Action is a must. While the concert was still in the planning stages, Irma, a second mega storm, wreaked havoc on Florida and the surrounding states. So the proceeds from tonight's telethon will be used to aid the victims of both storms. The cost from both disasters expected to climb upwards of more than $200 billion. Given the sheer size of the storm, almost the entire state of Florida has been affected by Irma. From Jacksonville north, subject to historic flooding, to the Florida keys in the south where Irma first struck as a category four storm on Sunday. FEMA says 90% of the homes on this set of sides have been destroyed or danged. My colleague David Muir with the air National Guard to survey the damage in the keys. You've been out there. You've seen the damage and the devastation. What are we looking at? You start getting down to mile marker 25, 23, you truly appreciate that a category 4 hurricane passed over that area. One out of every five houses is destroyed in that area. In this neighborhood, the first structure completely destroyed. The play ground beside it still standing. Farther down the road, a car with its windows blown out. Roof tops on front yards. Pthis mailbox, a symbol of the strength of the winds that came through here. Search he and rescue teams are going door to door in search of the people who did not evacuate. Irma has claimed the lives of at LE 15 people throughout Florida. While electricity has been restored to more than 2 million customers never Florida, tonight, over 4.3 million customers are still without power. Repair crews, more than 20,000 strong from 30 states and Canada, are working around the clock but many are now bracing for what may be another long night in the dark without air conditioning. It is intense. We take it step by step. One job at a time. In Lee county, at least 21 people hospitalized with carbon monoxide poisoning. Authorities spreading the word tonight to homeowners. If you have a generator, you must keep it outside. Restoring electricity to the whole state could take weeks. Kathleen Thompson has her power back. It just came on about two hours ago. What does it feel like? Oh, my gosh, I'll inviting my whole family over here. No one had power or food. Now we can take a shower. Several relatives are staying with her. 16. 16 people in a three bedroom house. Yes. But in some parts of the state, life is slowly returning to Normal. Take a look at this epic travel jam. Residents are finally able to go back home. Clean-up is underway but ocean drive, more like a beach than a boulevard. The beach is over here but the sand is over here. It just covered it. Adding to the headaches, the need for gas. For the most part, if you want to wait in line in Florida, you can get the necessities. But a much different situation in the caribbean. A lag of basic supplies is acute. Almost everything is broken down. We need water and food. Even as the French president macron visited today promising to help. We are trying to fix the situation regarding health, education, access to water, energy. Not just St. Martin. Last Wednesday, Richard Branson took to Twitter to say he was riding out the storm with others in his wine cellar in his private resort in the British Virgin Islands. His estate was destroyed by hurricane Irma. Since then he's helping with efforts, pledging to raise money for reconstruction projects. Taking a social media to bring attention to the desperately needed recovery. Back in the U.S. While the most recent spotlight has been on the destruction in Florida, Houston has been recovering slowly in the weeks since hurricane Harvey flooded the city, destroying buildings, inundating neighborhoods and pushing thousands from their homes in the shelters. Overwhelmingly devastating. It is a mess everywhere. 75 people died as a result of that storm. According to public safety, an estimated 37,000 home have been seriously damaged or destroyed. Our entire neighborhood is underwater. Today some neighborhoods in west Houston are still flooded and despite many relief efforts, some Houston residents are struggling to get back on their feet and rebuild. Everything we had down there is gone. Just overwhelming destruction at the hands of mother nature in the last few weeks. There are that's of people throughout who need our help. Tonight's telethon -- ??? ??? Raising more than $15 million in an hour. Please, give what you can. Just one small step in a huge rebuilding effort. For "Nightline," Miami, Florida.
This transcript has been automatically generated and may not be 100% accurate.