We get the alerts over the radio from Central. Greeters always have a radio so them and the team captains are the first to know at an attraction.I remember in 1990 (!) being in line for Jaws at Uni (the first version). We were held at the dock due to a storm. The dispatcher had a gadget that beeped everytime lightning within a defined radius was detected. Now you can get a graphical representation of it on the phone in your pocket. I’m sure park technology has come as far.
And yes, we got to ride Jaws version one