Unusually intense lightning strokes have been observed by optical sensors on the Vela satellite. These lightning flashes are over 100 times more intense than typical lightning. The lightning superbolts are characterized by optical power in the range of 1011-1013 W, have a duration of the order of 1 ms, and have a total fadiant energy greater than 100 J. In conjunction with sferies data the Vela trigger rates indicate that about two lightning flashes in 103 exceed an optical power of 1011 W and five flashes in 107 exceed an optical power of 3¿1012 W.