The flagship Surf Pool at Disney's Typhoon Lagoon is North America's largest wave pool and generates massive 6-foot (approx. 1.8-meter) swells. These are not your average gentle ripples; they are powerful, man-made waves that are preceded by a loud "sonic boom" or thundering sound to warn swimmers of the impending surge. The pool operates on a cycle, usually alternating between 10 minutes of big waves and 10 minutes of calm water. For serious surfers, Disney even offers private surfing sessions before or after park hours where the wave height can be adjusted and timed for professional-style practice. For casual visitors, it is a peer-to-peer "safety essential" to be aware that the 6-foot waves can easily knock an adult off their feet or push them into the rough concrete floor of the pool. If you aren't a strong swimmer, it is best to stay in the shallower "wading" areas where the waves break and lose their initial force.