Flashover or sparkler bottles? What caused deadly Swiss Crans-Montana Constellation bar fire?

The death toll in the deadly fire at the upscale ski resort of Crans-Montana in Switzerland has touched 40, as per the latest reports. According to authorities, over 115 have been injured, and many of the victims are young and have yet to be identified.

While a probe has been opened into the incident, authorities have not yet confirmed the cause. "Several hypotheses have been put forward," stated the canton's Attorney General, Béatrice Pilloud, who added that the leading theory at present is that of a  widespread fire that caused an explosion. “Several witnesses have been interviewed. Cell phones have also been recovered for analysis," he added.

Sparkler bottles

According to several reports by various Swiss, French, and Italian media outlets, the  possible cause of the fire is sparklers attached to bottles. They claim that a person perched on another’s shoulder had held the sparkler bottle aloft, which touched the ceiling. This was a common "show" at the establishment, according to reports.

"I think there were some ladies, waitresses, with bottles of champagne with little flares. They were too, too close to the ceiling, and well, it all caught fire suddenly," a witness told the Italian media outlet Local Team.

The witness added that he saw waitresses arriving with sparklers in champagne bottles before “total chaos” erupted.

A photo from the bar also shows a foam ceiling in the bar used for soundproofing, and sparkler bottles in the hands of many.

A video posted on YouTube to promote the establishment's parties shows bottles of champagne paired with sparkling fountain candles being served to customers, sometimes held on the shoulders of waiters. Another photo doing the rounds also showed a woman on a man's shoulders holding bottles of champagne, complete with "sparkling candles," near the bar's ceiling.

The official version is that the smoke appeared around 1:30 a.m. Shortly after, the fire was reported, and the alarm was triggered. Two minutes later, the first police and gendarmerie  patrols arrive. Firefighters have simultaneously contained the site.

Flashover?  

Authorities are also investigating whether a “flashover” is believed to have impacted the blaze. A flashover causes everything in a room to ignite almost simultaneously when hot gases rise to the ceiling and spread across the walls. The heat is so much that all combustible items in the room reach their ignition point suddenly, creating a fire.

“Flashover is when it’s when you no longer have objects in the room on fire. The room is on fire,” Steve Kerber, the Vice President and Executive Director of the Fire Safety Research Institute, told CNN.