Why Lock Cats Up When Windy?

The following are the protocols from Big Cat Rescue's training, classes and policies section:

Locking up Open Air Cats During Storms or High Winds

All open air cats should be locked in the roofed sections of their enclosures prior to or as soon as possible during severe storms, hurricanes, & tornado watches as well as if there have been several days of heavy rain or if winds reach 30 mph or higher.https://youtu.be/jENNeGH2iCk