An accident waiting to happen is an expression that describes a situation or condition that is highly likely to result in a catastrophic event. There are several synonyms for this phrase that capture the same sense of imminent danger. One such term is a ticking time bomb, which conveys the idea that a potentially hazardous situation is just waiting to explode. Another option is a recipe for disaster, which suggests that the ingredients are all in place for a calamitous event. Alternatively, a train wreck waiting to happen implies a sense of inevitability and impending disaster. Whatever term is used, the message is the same: caution is key to avoiding a disastrous outcome.