What do you suppose happened? A truck load flipped over??

yesterday around here a semi full of frozen fish lost its brakes or otherwise somehow wrecked coming off of a freeway off ramp, went over a small wall, across a bike trail and down into the river! I went by the spot later in the day when the truck was already gone, but much of the spilled fish was still being cleaned up. The lady who told me I could go through was right - it was a big pile of fish....