Rides were evacuated yesterday afternoon (Friday) when the park was alerted by its weather monitoring system of an approaching storm.
A statement said: "This type of weather front is not unheard of and we have very rigorous and well-practiced procedures in place for this type of situation. All of our outdoor rides that are affected by these conditions were evacuated as per our protocol.
"At around 4.15pm we believe that a lightning strike may have hit our Volcano ride and our engineers assessed the ride before re-opening.
"As soon as the heavy rain and lightning had safely passed, all other rides were reopened."
Hundreds of people took to social media to praise Fantasy Island for their actions.
Among them, Christine Lowe said: "Well done for keep us all safe - the bang was so loud."
Becky Oliver said: "Well done - that's brilliant that you responded so quickly and kept everyone safe. Dread to think what the outcome would havef been if someone was up there."
Tracy Wileman said: Well done Fantasy Island. Safety is paramount. Could have been a very different story."
Claire Louise said: "Thank goodness you evacuated and shut down immediately.... in the space of those five minutes , this could of been a totally different post we’d all be reading right now."