The cave is a tourist attraction with paths, stairs and handrails. It wasn’t raining when they went in but flash floods happen... in a flash. They had no idea when they went in. Nature happens.
A few years ago, I drove over to pick up someone and made a quick turnaround to drive home. The sun was shining and not a cloud in the sky though it had rained the day before. Half an hour later and almost home but bam! the water suddenly rushed down from the hills and we were cut off in a flash flood.
I can’t blame the coach. The boys’ parents aren’t blaming him.
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Well then, I guess everything is cool.
All I know from observing "rain events" for at least 60 years, I would have tried to MAKE SURE that there was quite a minimal chance of THAT "rain event" before allowing these kids to enter the cave for really NO great reason.