Source : Webster's Revised Unabridged Dictionary (1913)

Impendence \Im*pend"ence\, Impendency \Im*pend"en*cy\, n.
   The state of impending; also, that which impends.
   ``Impendence of volcanic cloud.'' --Ruskin.

Source : WordNet®

impendency
     n : the state of being imminent and liable to happen soon [syn:
         {imminence}, {imminency}, {imminentness}, {impendence}, {forthcomingness}]