"If an airplane can't safely come to a stop on the normal runway surface".

The FAA says the safety system is in use at 63 airports nationwide, including San Francisco, Oakland and Monterey.

Although the cause of the overrun has yet to be determined, the airport was reporting inclement weather conditions at the time of the event.

No injuries were reported among the 112 passengers and five crew members on board, the airline said.

Passengers were seen evacuating from the aircraft via an inflatable slide shortly after. Failure to abort the landing approach and an air-traffic controller's positioning of the plane for landing also contributed, the NTSB determined. "They go over these E-MAS beds and the landing gear slowly sinks into these blocks of crushable concrete", Yakel said.

The plane was said to have landed during torrential rain.

The airline is refunding the cost of the passengers' roundtrip airfare and rebooking trips for those with connecting flights, a Southwest Airlines spokesperson said.

The airport is open, and all airlines are operational, the airport tweeted.

Around the time of the incident, visibility at the airport dropped to 1 mile.

It skidded off the end of the tarmac during torrential rain in the Los Angeles County area. Its monthly average is 2.4 inches.