A Checklist of legal issues to consider when a company has experienced an extreme event that prevents performance of a contract and is considering invoking a force majeure clause. The Checklist includes a discussion of contractually specified force majeure events and notice requirements, catch-all language in force majeure clauses, requirements regarding foreseeability of and control over the force majeure event, the force majeure event as the proximate cause of non-performance, mitigation by the invoking party of the effects of the event, the interaction between force majeure clauses and other contractual remedies provisions, and defenses to performance that may apply if a force majeure defense is not available.