As he touched down Arriving the aircraft began Process_start to slide Motion backwards on the wet surface .

Watson attempted to retract Removing the landing gear to arrest Arrest the slide but this failed and the aircraft slipped Motion_directional backwards off the container and onto the roof of a van parked Placing on the deck .

The van partially held up Hindering the fuselage and stopped Preventing_or_letting a further slide .

An earthquake Catastrophe at 8:32:17 a.m. PDT ( UTC−7 ) on Sunday , May 18 , 1980 , caused Causation the entire weakened Cause_change_of_strength north face to slide Motion away , creating Creating the largest landslide ever recorded .

A period of heavy rain led to Causation a build-up of water within the tip which caused Causation it to suddenly slide Motion_directional downhill as a slurry , killing Killing 116 children and 28 adults as it engulfed Destroying the local junior school and other buildings .