In the early hours of Jan. 1, 2026, a fire ripped through Le Constellation bar in Crans-Montana, Switzerland, killing 40 people and injuring 116, many of them severely.
Investigators believe the blaze began when sparklers on champagne bottles were held too close to the ceiling, igniting interior materials. The investigation is ongoing, and it is premature to draw conclusions about individual actions or responsibility. But fires do not need villains to be instructive.
What matters is not the spark itself, but the system into which that spark was introduced.
Fire safety, as history keeps reminding us, is not about eliminating ignition. We will always cook, heat, wire, decorate, celebrate and repair. Fire prevention is about ensuring that when ignition happens, as it inevitably will, it does not propagate.
My research has focused on how disasters are prevented, and how warning signs are missed when systems drift or protections are taken for granted. Fire safety is one area I have examined, and it reveals recurring patterns that are relevant to understanding this tragedy.
Fire as a contagion
(AP Photo/ Antonio Calanni)
For one thing, fire behaves less like an accident and more like a virus. It spreads through available fuel, follows paths of least resistance and accelerates when conditions are favourable. The historian Stephen Pyne describes fire as a “contagion of combustion.”
Like disease prevention, fire safety has never relied on a single safeguard. Instead, it depends on layers of them: materials that resist ignition, detection systems that identify problems early, compartmentalization that limits spread, suppression systems that slow or extinguish flames and trained humans who know how to respond when technology falters. When fires become destructive, it is almost always because multiple layers fail at once.
The Reason Model and fire prevention
The Reason Model, often visualized as slices of Swiss cheese, helps explain why disasters occur even in systems designed to be safe.
Each slice represents a layer of defence. Each slice also contains holes, imperfections, gaps and latent weaknesses. Most of the time, those holes do not line up, but when they do, harm passes through.
Latent conditions for fire exist everywhere: dry materials, electrical wiring, human fatigue, budget constraints, informal workarounds. These conditions are usually harmless until they align. The spark is not the cause of the disaster. It is merely the moment when all the holes line up.
Celebration and risk perception
The New Year’s fire at Le Constellation bar occurred in a celebratory setting. That matters, because celebration changes how we perceive risk.
Celebratory spaces often bring together the very conditions fire exploits: crowds, alcohol, decorations, reduced vigilance, temporary installation and informal rule-bending “just for the night.” When those conditions align with flammable materials or limited escape access, the margin for error shrinks dramatically.
Latent conditions are not evenly distributed across time. They cluster during moments of exception — holidays, renovations, special events when normal routines are suspended.
Notre-Dame: when multiple failures occur
(AP Photo/Vanessa Pena)
When the Notre-Dame Cathedral nearly collapsed in a fire in April 2019, it shocked the world. The building was not neglected. It had a sophisticated fire detection system with more than 160 sensors. Fire wardens patrolled the attic three times daily. A firefighter was permanently stationed on site. The Paris Fire Brigade had trained for exactly such a scenario.
And yet, the fire still spread.
An alarm triggered at 6:18 p.m., but a misinterpreted code sent a guard to the wrong attic. A fatigued technician, covering a double shift, struggled to escalate the alert. The system detected the fire, but it did not automatically summon the fire department. By the time the correct location was identified, 30 minutes had passed. The roof timbers, made of centuries old dry oak, were already burning uncontrollably.
Notre-Dame did not burn because no one cared. It burned because multiple failures aligned: ambiguous alarm codes, human fatigue, delayed escalation and architectural features that lacked compartmentalization or sprinklers. A fire protection engineer later remarked that the only surprise was that the disaster had not happened sooner.
Rarity breeds complacency
One of the paradoxes of modern fire safety is that it works so well it becomes invisible. Between 1980 and 2024, the rate of reported fires per 1,000 people in the United States fell by more than 60 per cent, according to long-term data compiled by the National Fire Protection Association. Sprinklers, fire doors, smoke detectors, compartmentalization and education campaigns have made large fires rare.
But that rarity can breed complacency.
When a system prevents disaster hundreds of times, it becomes tempting to ignore precautions. Doors are left open. Materials are substituted. Alarms are misunderstood. Redundancies are trimmed.
The holes in the safety system widen quietly. Then, eventually, they all line up.
Learning from tragedies
(AP Photo/Baz Ratner)
The Swiss fire had its own specific causes, and those details matter. But the broader lesson is neither new nor obscure. Fires do not escalate only because people are reckless. They escalate because systems drift away from the conditions under which they were safe.
Fire safety is an engineering and organizational project. It requires constant attention to small details, especially when nothing seems wrong. It demands respect for fire and its destructive potential.
We have learned, repeatedly, how to prevent fires from spreading. Every major advance, from fire doors to sprinklers to automatic shutoff systems, came from studying failures where containment broke down.
The tragedy is not that we do not know what works. It is that, over time, we forget to be afraid.
