Transcript for People planning to stay put for Irma
A million people may be trying to get away, but that means millions more will be staying in the storm zone, and as you look across here at Miami, you can see so many high-rises and the question tonight, can the construction of the windows withstand a category 4 hurricane? We asked ABC's Tom llamas to take us up into the buildings. How much faster and more powerful will the winds be, the higher you go? Reporter: Tonight Miami's glass towers and the cranes that build them causing concern hurricane Irma could shatter it all. Those are big targets out there. Again, we're going to lose buildings that are going to have to be repaired, but I don't think buildings are going to completely collapse. Reporter: 25 cranes are being secured before the storm, those that live near them told to evacuate. Developers and builders ABC news spoke with tell us buildings in downtown Miami will hold up, but that high-rises could sway, some up to 12 inches. I expect to feel some here. We did feel it here during Matthew and that was tropical storm. Reporter: People in high-rises don't have to worry about debris like you down on the ground but up here, 50 stories, with a view like this, you do have to worry about something else. The wind is much more powerful up here. Hurricane researchers tell us on the fiftieth floor a category 4 hurricane winds at 140 miles per hour would be 220 miles per hour that high up. South beach resident Andres asion will ride out the storm in his 21 St floor condo. He has storm impact windows and cameras set up to watch the storm apprach. But even he has a plan B. "My plan if it gets too crazy ill go into the elevator shaft and it's like a fortress." Reporter: Other Miami residents lined up outside of this packed Costco, trying to prep by getting supplies that are now scarce. Even water, tough to find. Tom, people are not going to forget what you just reported. How much stronger those winds will get. Stay away from the windows here in Miami. Reports of price gouching. Are people being ripped off as they try to prepare? Reporter: In some cases they are. I just got off the phone with the office of attorney general here in Florida. Since Monday, David, get this. They have received 4,000 complaints of price gouging.
This transcript has been automatically generated and may not be 100% accurate.