It could be...according to NFL Rules. In this case a reschedule who probably happen.
Emergencies and Unfair Acts
Emergencies -- Policy
The National Football League requires all League personnel, including game officials, League office employees, players, coaches, and other club employees to use best effort to see that each game -- preseason, regular season, and postseason -- is played to its conclusion. The League recognizes, however, that emergencies may arise that make a game’s completion impossible or inadvisable. Such circumstances may include, but are not limited to, severely inclement weather, natural or man-made disaster, power failure, and spectator interference. Games should be suspended, cancelled, postponed, or terminated when circumstances exist such that commencement or continuation of play would pose a threat to the safety of participants or spectators.
Authority of Commissioner’s Office