Editor’s note: This story contains descriptions and video that readers may find disturbing.
As young partygoers rang in the New Year at a crowded bar in the Swiss Alps, the celebrations quickly turned into a nightmare when a devastating fire ripped through the basement, killing at least 40 people and injuring 119 others.
Switzerland’s president has described the fire at Le Constellation in Crans-Montana as one of the country’s “worst tragedies”. As families anxiously await news about missing loved ones and experts work to identify the victims, authorities are still piecing together the origins of the fire and how it spread so quickly.
Swiss authorities said on Friday that champagne fireworks may have been the cause of the fire, but an official investigation was ongoing. Emerging videos and eyewitness accounts reveal a host of deadly dangers: ceiling paneling that caught fire easily and a crowded bar packed with young patrons who flocked to narrow escape routes.
carnival night
Located in the heart of Crans-Montana, a luxury sky resort in the French- and German-speaking canton of Valais, Le Constellation is a popular nightclub among locals and tourists alike.
According to witnesses, there were about 200 people at the venue on New Year’s Eve, ready to celebrate 2026 with music, drinks and dancing.
Sparks turn into smoke
Images widely circulated online showed workers wearing motorcycle helmets sitting on the shoulders of others holding champagne bottles containing fireworks among the crowds.
One video showed at least six bottles being held in the air as flames and smoke spewed from the ceiling.
An image shared on social media showed a waiter appearing to hold a champagne bottle with a sparkler attached. CNN has blurred part of this image to protect identity. – from social media
Another image shows the ceiling on fire. CNN has blurred part of this image to protect identity. – from social media
Experts believe the fireworks appeared to ignite acoustic panels in the ceiling, a material designed to improve sound but which can also be highly flammable.
Independent fire consultant Stephen McKenzie described it as “plastic petrol”, adding: “That’s why we’re seeing so many reports of young people suffering first, second, third and, unfortunately, fourth degree burns.”
Switzerland’s chief prosecutor, Beatrice Pilloud, told reporters on Friday that investigators were looking into whether foam paneling was installed at the bar and whether it complied with regulations.
The fire spread quickly
Once a fire breaks out, it spreads quickly.
One video showed a young man trying to put out the fire with a cloth, while others were recording on their phones or continuing to dance, seemingly unaware of the imminent danger.
An eyewitness said: “After the ceiling caught fire, within about 10 seconds the entire nightclub was on fire.”
terrible escape
Party-goers rushed up the narrow staircase as smoke filled the lounge and fire roared.
Video verified by CNN showed dozens of people trapped at the exit, with one jumping out of a window and thick smoke engulfing the building.
McKenzie explained that the fire spread quickly through a process called flashover, in which nearly everything in a room catches fire at about the same time.
He said “burning intensified at the ceiling,” causing the fire to “spread laterally.” This process is like “a pebble falling into the sea”, the smoke ripples from the sides and begins to “preheat” everything in front of it.
McKenzie said when a fire door is open, a “stack effect” can occur, accelerating the upward flow of smoke and flammable gases. “The smoke actually caught fire – a ‘flashover,'” he added.
On Friday afternoon, Swiss prosecutor Pillou said all signs supported this theory: “As things stand, everything points to the fire being caused by pyrotechnics or flares in champagne bottles placed too close to the ceiling, which quickly led to a flash fire.”
Le Constellation is divided into at least two floors, with stairs leading to the basement, as shown in photos posted by the bar’s management on TripAdvisor in August 2016. – from Le Constellation
Laetitia Place, a 17-year-old partygoer from Lausanne, told of her harrowing escape from the fire, saying the squeeze at the narrow exit made it difficult for others to get through.
“The first stairs were easy to get through because they were wide and so on. But after that, everyone was pushing on that little door, so we all fell down, we were piled on top of each other, some got burned, some died next to us,” the teenager told Reuters.
Video obtained by CNN showed multiple people lying motionless outside while Standard tried to help.
Local resident Samuel Rapp, 21, witnessed the aftermath.
“There were people screaming, and then there were people lying on the ground, probably dead. They had jackets over their faces – well, that’s all I saw, that’s all. And then I got video of people trying to get out, but they were trampling on each other, so it was hard to get out. There were people yelling, saying, ‘Help me, please help us.'”
Emergency services arrive
Swiss emergency services responded within minutes of the fire, taking the injured to hospitals across Switzerland and abroad. About 50 patients have been or will be transferred to hospitals in other European countries for specialist treatment, authorities told reporters on Friday.
This screenshot from police video on January 1 shows the aftermath of a fire at the Crans-Montana ski resort in Switzerland. – Valais cantonal police
Edmund Coquette told CNN affiliate RTL Germany that he saw “bodies in the street” and young people with “completely burned faces” and missing fingers.
Dr. Robert Laribaud, director of the emergency department at the University Hospital of Geneva, told CNN that most of the patients were between 15 and 30 years old, and many suffered “extremely serious injuries” from flashover and possible flashback.
Flashfires often result in severe burns, particularly to the face, neck, and upper extremities, often accompanied by severe inhalation injuries from radiant heat and superheated gases. Backlash is an oxygen-powered explosion that can cause instantly fatal burns and inhalation of toxic materials.
Swiss officials said on Friday that police had interviewed the bar’s two French owners and that an investigation was underway into the circumstances of the fire and how quickly it spread.
CNN has contacted the bar owners through them but has not yet received a response.
Meanwhile, as of Friday evening, many of the victims and loved ones of the injured were still waiting for answers as authorities continued to identify the dead.
CNN’s Martin Gaulando, Billy Stockwell, Henrik Pettersson, Nick Robertson, Joseph Ataman and Duarte Mendonca contributed.
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