वर्षोपल इवाभाति नीरमेवाभ्रयोगतः ।वर्षोपलविनाशेन नीरनाशो यथा न हि ॥ १२ ॥
In plain words
Water — nothing but water — appears as hail, and only because it met the cloud. Just as, when the hail is gone, not a drop of water has been lost.
Close to the Sanskrit
Water itself appears like a hailstone through conjunction with the cloud; just as, by the destruction of the hailstone, there is indeed no destruction of the water.