Meteorologists often talk about “power flashes.” These bluish “apparent explosions (when viewed from a distance) occur when power lines are disconnected or create short circuits with electrical transformers. KXAS TV in Ft. Worth has video. The snow weighted down tree limbs which sagged onto the lines and created the flashes.
Power flashes also occur in ice storms, high winds, and tornadoes. Flashes are one of the surest ways of confirming a tornado at night.