Last weekend I went to an outdoor concert / festival. There was a rock band playing inside a metal pole barn-like building. I could see fierce lightning out in the distance, and then someone announced over the bands microphones that there was a severe storm approaching and everyone should exit the large tents, and either leave or come into that tin building. Most people came into the building and the band went back to playing music. All of a sudden I could see the trees outside bending way over and the lightning was close, and even the thunder could be heard over the loud amplifiers. Seconds later the rain came down in buckets and the water coming off that roof was like a waterfall, and someone closed all the sliding doors.
Now I still dont know where all the water came from, since that building was on the high end of the grounds, but suddenly there was a river coming thru the building. It only took a minute for the water to reach a depth of about 18 inches. It pushed the doors inward on the upper end of the building and outward on the lower end as all the water rushed by carrying all the trash from the ground with it. A few of the wooden picnic tables were afloat, but people began to stand on them and secure them. The band was on a 5 foot tall stage, so they were dry except gusts of rain that managed to blow in the cracks by the doors. The younger audience just played and danced in the water and were splashing each other, while us older folks just stood on tables or decided our shoes were dirty and needed a washing. No one seemed too upset, of course many were drinking. I had not been drinking and was cautious and watched the storm thru the cracks next to the door. I also noticed that there were people lifting mic cables and other wires that were hanging off the stage. That's when I decided I should go make sure they were plugged into GFI outlets. They were, so I figured everyone was safe. Thats when some official came onto the stage and told the band they were going to cut the power to the sound system. I also saw someone telling the food vendors to unplug everything.
While I so understand the reasoning behind this, and was more worried about the food vendors who were not on GFI outlets, and had extension cords all over the place to their cash registers, coolers, etc. But I really dont think the band needed to be stopped as long as they were plugged into GFI's. After all, that's the purpose of having them.
It was dissapointing, but was a night I will never forget. When people were leaving, some found their cars in the lower lot with water halfway to the roof, and covered with trash. I now suspect that the storm sewers backed up above that building. Regardless the amount of water coming off that roof, there was just too much water for simply what came off the roof and accumulated on the asphalt outside.