When an unforeseen event makes performance of a contract obligation impracticable (impossible or unrealistic), the seller may claim that its nonperformance is excused. To analyze a claim of impracticability, determine whether all of the following apply:
- 
The event occurred after the contract was made. 
- 
Performance became impracticable because of the event. 
- 
The nonoccurrence of the event was a basic assumption of the contract. 
- 
The party seeking to be discharged carried the risk of the event’s occurring. 


