HASSELT, Belgium – The Britrock band Skunk Anansie had the crowd hopping and gyrating when a sudden, fierce storm began pelting the main stage — and the thousands watching them — with rain and hail.

The storm shredded the annual Pukkelpop outdoor rock festival Thursday evening, blowing down huge canvas tents, uprooting trees and flinging multistory metal scaffolding towers across the grounds.

Organizers said five people were killed and 140 injured, 10 of them seriously.

Skin, the band’s lead singer, described the chaos on the band’s Facebook page, saying “a burning hot sunny day turned into a mini-hurricane.”

“(A) tower fell onto our truck, we had to run for our lives mid-set as hail hit the stage and the wind began to tear it to pieces,” she wrote. “This was the scariest moment I have ever seen or felt in my 20 years of being an artist.”

Toon van Wemmel, 26, a graphic designer from nearby Leuven, said, “The hailstones came down so hard they caused bruises.” He and his partner ran away from the main stage, turned around and saw trees crashing down where they had stood less than a minute earlier.

Officials said the dead were all Belgians, ranging in age from 15 to 59. They were not immediately identified.

Officials canceled the last two days of the three-day Pukkelpop festival Friday and blamed unprecedented weather conditions in the town.

Hilde Claes, the mayor of Hasselt, spoke of a “nightmare” and said the town had never seen a storm like the one Thursday.