What happens when a torch flame goes out with a loud pop or snap?

When a torch flame goes out with a loud pop or snap, it indicates that a backfire has occurred. A backfire happens when the flame momentarily travels back into the mixer or the tip of the torch, often due to an interruption in the gas supply or a leak in the hose. This sudden backflow can create pressure changes in the system, leading to that distinctive popping sound.

Recognizing a backfire is crucial for safety, as it suggests potential issues with the torch setup that need to be addressed to prevent further occurrences or hazards during cutting operations. It's important to ensure that all components of the cutting setup are in good working condition to avoid backfires, which could lead to injury or equipment damage.

The other options refer to different scenarios that would not typically involve the loud popping sound associated with a backfire. For example, an explosion would be a much more catastrophic event, while a damaged torch would likely not produce a sound characteristic of a backfire, and a gas leak usually presents with a different type of hazard.