A skeleton crew is the minimum number of personnel needed to operate and maintain an item at its most simple operating requirements, such as a ship or business, during an emergency and, at the same time, to keep vital functions operating.
Some example uses of skeleton crews include:
shipboard: the barest minimum number of personnel to keep the ship operating after it has been damaged and awaiting tow to port.
hurricanes and typhoons: the least number of personnel to remain at a business location during a major storm to monitor conditions and to make emergency repairs, if possible.
inactivity: the least number of personnel necessary to keep an inactive facility from being vandalized, such as a Texas Tower, a commercial building in transition between owners, etc.
temporary closings: the smallest number of employees to monitor and maintain the facility while it is otherwise shut down for a holiday, strike, etc...