Dunkirk - a crisis in which a desperate effort is the only alternative to defeat; "the Russians had to pull off a Dunkirk to get out of there"

exigency - a pressing or urgent situation; "the health-care exigency"

critical point, crossroads, juncture - a crisis situation or point in time when a critical decision must be made; "at that juncture he had no idea what to do"; "he must be made to realize that the company stands at a critical point"

situation - a complex or critical or unusual difficulty; "the dangerous situation developed suddenly"; "that's quite a situation"; "no human situation is simple"

juncture, occasion - an event that occurs at a critical time; "at such junctures he always had an impulse to leave"; "it was needed only on special occasions"

emergency, exigency, pinch - a sudden unforeseen crisis (usually involving danger) that requires immediate action; "he never knew what to do in an emergency"