11.   Dense foliage and bad weather prevented rescue helicopters from getting anyone to the site.

12.   Fresh storms on Wednesday had prevented helicopters and boats from landing then, hours after the eye of the hurricane had passed.

13.   Heavy fog prevented helicopters from reaching the crash site Thursday, and bad roads stopped rescue vehicles miles from the wreckage.

14.   In Jamaica, rain prevented army helicopters from completing food drops until late Saturday evening to several communities isolated by landslides blocking roads.

15.   Officials will place mesh coverings over jails that house the most dangerous inmates to prevent helicopters from landing in prison yards, Justice Minister Marylise Lebranchu said.

16.   Poor visibility prevented helicopters from taking off.

17.   Snow and poor visibility Wednesday prevented a helicopter from plucking four climbers and five park rangers from near the top of Mount Rainier.

18.   Strong winds prevented the helicopter from spending much time over the area where the village of Abkennareh is located.

19.   Strong winds and snowstorms had at times prevented the helicopter from even flying over the site.

20.   The other three, who were not injured, activated an emergency locator beacon, but bad weather prevented a helicopter from flying them out Wednesday.