Sorry to hear about that, but glad that nobody was hurt.
It would be quite possible for a surge of power to knock out part of the chroma circuitry of a TV. With no chroma signal at the decoder, the set will act just as it would if it were receiving a black-&-white signal.
If the colors at the bottom of the screen are weird (i.e. not what they should be) then it may well have left the shadowmask in the tube magnetized, or even distorted out of shape.
