Dozens of firefighters battled to save the country's longest dry ski slope as a blaze gutted the main building.
The fire was still burning five hours after crews were called
The fire at Wycombe Summit and Snowboard Centre in High Wycombe, Bucks, broke out on Tuesday morning.
At its height 50 fire crew fought the flames and managed to stop them spreading to the 300m main slope.
Five hours later a Bucks Fire Service spokesman said 30 remained at the centre where there were still pockets of fire after the building collapsed.
Building caved in
Divisional officer Darryl Keen said the fire was believed to have started in the centre's kitchen when a minor gas leak ignited.
He said officers called to the centre just before 1100 GMT found a fast-developing fire.
At 1600 GMT they were still damping down areas difficult to reach after the building caved in and trying to salvage what they could.
He said crews had worked hard to stop flames spreading to the ski slopes which were virtually undamaged.
No-one from the centre was available for comment.