A glass panel on the popular slide suddenly ripped free under the force of rushing water.
Multiple inflatable rafts then crashed straight into the upturned sheet.
Riders had no chance to stop or steer clear in the fast current.
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Four tourists suffered bumps and bruises in the pile-up.
One visitor suffered a cut finger from the cracked glass, as reported by Need To Know.
The incident took place at the Hongma Mountain Rafting Scenic Area in Liuzhou City in Guangxi Province, China, yesterday afternoon (12 Aug).
Footage showed the glass panel prised up at the end of the slide, standing at a sharp angle after the flow flipped it.
Four or five rafts then slammed into the barrier in quick succession.
Other tourists swam over without safety gear and dragged the panel aside to prevent possible disaster.
Park staff rushed the injured for medical checks straight away.
The attraction operator will cover all related costs.
The waterslide has since been shut indefinitely for repairs.
Tourism officials ordered a halt to every water-based activity at the site the following day.
The move aims to clear safety risks and upgrade the facilities.
Visitors have been told not to enter closed or unfinished areas.
One report linked the failure to possible ageing of the glass sealant.
The exact cause is still being examined.
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