तदा then, गगनम् sky, आतपापाये overcast with, विद्युन्मालासमाकुलैः like flashes of lightning, घनैःइव like clouds, विविधैः different kinds, बाणैः arrows, सततम् everywhere, बभूव seemed

Then the sky overcast with arrows of different kinds seemed like clouds with flashes of lightning.