Modifiers matching contingency:

• unforeseen,
• unavoidable,
• unexpected,
• new,
• natural,
• specified,
• adverse,
• idiosyncratic,
• major,
• future,
• routine,
• unpredictable,
• social,
• financial,
• external,
• immediate,
• particular,
• single,
• negative,
• historical,
• unusual,
• usual,
• permanent,
• unforeseeable,
• acute,
• unpleasant,
• complex,
• remote,

Simple categories matching unforeseeable:

• reason,
• event,
• disaster,
• calamity,
• situation,
• disturbance,
• risk,
• incident,
• circumstances,
• setback,
• change,
• development,
• inactivity,
• occurrence,
• thing,
• cause,
• catastrophe,
• condition,
• circumstance,
• contingency,