Kokomo Leisure Time, a manufacturer of above-ground pools, receives an order for 10,000 pools from a major club warehouse retailer, Mallmart. The company manufactures and ships 5,000 of the pools before a tornado severely damages its factory. Kokomo Leisure Time notifies Mallmart that it will be unable to fulfill the latter half of the order.

Is this an exception to the perfect tender rule? If yes, why is it an exception? Defend your answer.