Lessons of Switzerland's Crans-Montana Fire

“In the early hours of New Year's Day, fire tore through Le Constellation, a basement bar near the Swiss resort of Crans-Montana, killing at least 40 people and injuring more than 110. Many victims were teenagers. Investigators say sparklers likely ignited flammable acoustic foam on the ceiling, and witnesses described flames racing overhead before many patrons understood the danger. Videos show young people, surrounded by fire, trying to put it out using their clothes. What exactly led to this tragedy will emerge in an investigation, but some lessons are already clear -- as is the high cost of not heeding them.

 

The Crans-Montana fire bears the signature of flashover, the terrifying phenomenon by which a growing fire ignites much of a room nearby simultaneously. As America's National Institute of Standards and Technology describes it, flashover occurs when a fire's gases become so hot -- exceeding 1,100 degrees Fahrenheit -- that the intense heat ignites exposed surfaces almost at once, suddenly engulfing an entire space. In a low-ceiling basement lined with combustible finishes -- as Le Constellation seems to have been -- a small fire can rapidly generate a superheated smoke layer near the ceiling that gradually expands downward. Once that layer reaches critical temperature, the entire room can catch fire in seconds, turning a crowd-control problem into an inescapable inferno.

 

Many Western countries allow bars and nightclubs to be built in exceedingly dangerous ways, through either weak building codes or lack of enforcement. Although we can't know whether Le Constellation complied with regulations and inspections until there's a full investigation, the Crans-Montana fire carries urgent warnings for regulators around the world and raises questions about Switzerland's fire-safety regulations and enforcement.

 

The disaster's first blunt lesson is about egress. Reporting indicates that the only exit available from Le Constellation's basement space was a narrow door at the top of a single staircase. Media report Le Constellation had a second exit but that it was locked to prevent people from leaving without paying. Even under perfect conditions -- i.e., in controlled research -- the math of one exit is unforgiving. In a densely packed space, as is often the case in nightclubs, evacuation observations show that between 55 to 79 people a minute can pass through a 3-foot-wide exit. Clearing a crowd of 300 -- about Le Constellation's maximum capacity -- would take four to six minutes. In a fire like that at Crans-Montana, there isn't that kind of time.

 

A second exit would have saved more lives, but it might not have been enough -- especially with one exit at the top of unprotected stairs. Local conditions make all the difference. In real fires, with darkness, smoke, people in various states of injury impeding one another, falls on stairs, counterflows and hesitation, theoretical egress capacities inferred from other evacuations break down.

 

Crans-Montana's second lesson is about materials. Many nightclub fires share a common factor: flammable soundproofing foam and interior finishes that cover much of the space and can ignite easily.

 

In fire-engineering terms, many nightclubs contain the fuel load of an entire residential condominium, the ignition sources of an industrial site, and the evacuation constraints of a submarine. From an emergency-management point of view, these situations can become deadly in about 90 seconds -- far outpacing evacuation models. Codes try to break this chain by restricting interior finishes based on flame spread and smoke-development performance. Switzerland's likely need to be re-evaluated.

 

The third lesson is on the importance of layering passive and active fire protection. Passive measures include multiple remote exits, protected stair enclosures, compartmentalization, smoke-tight doors and interior linings that resist ignition and limit heat release. Active measures include fire detection or alarms, emergency lighting and signs, suppression (notably sprinklers) and staff trained to stop entertainment, turn on lights and evacuate early.

 

Case studies by America's National Fire Protection Association of nightclub fires in Europe and the U.S. repeatedly show that when sprinklers are absent and interior finishes are too flammable, rapid fire growth overwhelms occupants before they can escape. The International Fire Code in 2018 added a sprinkler requirement for bars and nightclubs with occupancy over 300, but adoption varies across America and Europe. In Switzerland, cantonal fire-safety authorities may require sprinklers for occupancies of more than 300 people.

 

If investigators confirm the early reports of an apparent flashover, a lack of sprinklers and a difficult, single point of egress, Crans-Montana will join a grim list of fires that were foreseeable. These spaces were essentially engineered, by layout, materials and missing layers of protection, into tragedy.

 

Fifty years ago, scientists tried to limit fires by studying the results or pouring freshwater into scale models of rooms filled with saltwater, trying to mimic the interaction between smoke and air in a fire. Today, between the forensic reconstruction of fires and sophisticated modeling, we can understand fires with precision smoke and heat movements, ventilation effects and the interaction of sprinklers. Evacuation modeling can estimate how long it takes to get out, even taking into account the complexities of a real fire.

 

It's possible to do better. Patrons can protect themselves by locating exits whenever they enter a bar and noting their routes to them. Building and fire regulations need to catch up with technology and the lessons of preventable disasters like Crans-Montana, most notably the installation of sprinklers. Too often regulators and businesses don't think of the worst case scenarios. As a consequence, under real-world conditions, current safety measures can go up in smoke.

 

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Mr. Synolakis is a professor of civil engineering at the University of Southern California. Mr. Karagiannis is a disaster prevention expert at the Academy of Athens.” [1]

 

1. Lessons of Switzerland's Crans-Montana Fire. Synolakis, Costas; Karagiannis, George.  Wall Street Journal, Eastern edition; New York, N.Y.. 05 Jan 2026: A15.