Swiss bar fire: Death toll rises to 47, investigators suspect 'flashover' caused blast

A woman leaves flowers outside the 'Le Constellation' bar, after a fire and explosion during a New Year's Eve party where several people died. (Photo: Reuters)

The death toll has risen to 47 from a devastating fire during New Year’s Eve celebration at a Swiss ski resort as investigators said a phenomenon known as a “flashover" may have triggered the deadly blaze.

During an earlier press conference, Valais canton attorney general Béatrice Pilloud said investigators were examining whether a flashover — a sudden ignition of all combustible materials in a confined space — caused the explosion and ensuing fire.

“There are a lot of circumstances to clarify, several hypotheses were put forward," Pilloud said. “The main theory we’re prioritising is a flashover that provoked a rapid explosion. Several witnesses have been heard and there are telephones that were recovered to be analysed."

The fire broke out shortly after midnight at Le Constellation, a basement-level venue packed with hundreds of mostly young revellers, in the Alpine resort of Crans-Montana.

Authorities said many of the injured suffered severe burns, complicating identification efforts. Switzerland’s president described the tragedy as unprecedented, while neighbouring countries offered medical assistance.

Switzerland announced five days of national mourning for the victims of the Le Constellation bar fire in Crans-Montana, starting Thursday. Flags have been lowered to half-mast on public buildings across the country in memory of those killed.

Survivors in one of the deadliest tragedies in modern Swiss history described chaos as flames spread rapidly, filling the club with smoke and cutting off escape routes. Two women told French broadcaster BFMTV they were inside when a male bartender lifted a female colleague onto his shoulders as she held a bottle topped with a lit candle. According to their account, the flame caught the wooden ceiling, and the fire spread within seconds.

What is a flashover?

According to the US-based National Fire Protection Association (NFPA), a flashover occurs when hot gases rise to the ceiling of a room and spread across walls, dramatically increasing temperatures. Once the heat reaches a critical point, all combustible items in the space ignite almost simultaneously.

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

'Everyone was screaming'

Witnesses described a deadly crowd surge as people tried to escape through a small exit. “It was absolute panic, everyone was screaming,” Emma and Albane told BFMTV, describing how crowd movement became uncontrollable as smoke thickened.

Another witness said people smashed windows to get out as flames engulfed the venue. He described seeing badly injured people outside and parents arriving in cars, desperately searching for their children.