Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
fulgŭrātĭo, ōnis, f. [fulguro], sheetlightning, lightning: fulguratio est late ignis explicitus: fulmen est coactus ignis et impetu jactus, Sen. Q. N. 2, 16; 2, 12; 21; 56.
In plur.: nubes mediocriter collisae fulgurationes faciunt: efficiunt majore impetu pulsae fulmina, Sen. Q. N. 1, 1, 5.