Now I assuming that somehow the tadpoles were in a body of water that somehow got sucked up very rapidly in some kind of water cyclone/tornado funnel and hurled into the distance, at which point it looked like they were raining.
I highly doubt they were swimming around in the clouds.
And if we assume that it is a supernatural rain of tadpoles, what gives? Some kind of new stealth operation? Regular frogs would be too dramatic?