Aerial views over Orlando revealed just some of the damage the Florida city sustained in the wake of Hurricane Irma, including damage to mobile homes that had their roofs ripped away.

Only a fraction of mobile homes in Florida were strapped down with the kind of hardened braces meant to withstand fierce storms before Irma hit the state, experts said, leaving more than a half-million homes vulnerable to serious damage.

About one-third of Florida’s roughly 850,000 mobile homes were installed to current code, according to industry data. The standards were devised after hurricane Andrew struck Florida in 1992, uprooting thousands of mobile homes like tin cans.

The rest still have their original underpinnings, making them even more vulnerable to a catastrophe like Irma, whose maximum sustained winds on Sunday afternoon were 120 miles per hour (195 kph), with storm surges expected to rise above 15 feet (4.6 m).

Orlando’s Walt Disney World, a major tourist attraction for the state, appeared largely unscathed, according to the helicopter crew of the local NBC news affiliate flying over the city.