Because she leaves, the rain turns into tears for those grieving leaves..
The following is how "I" felt while writing this song:
As his love is killed under that tree, he starts running towards her while she falls slowly, and the wind starts blowing gently, then the transformation of the sounds begin (wind into cello). The clouds shut the light of the sun just coming out of the eclipse. The rain starts to fall on the leaves of the tree (piano), as if even the leaves grieve over this death (grieving leaves). His sadness starts to surface as he holds her in his arms (2nd cellos); her soul slowly leaves her body (solo sopranos). His cries get deeper, as he starts to lose control, her soul whispers to him (flute). His sadness fights back against her whispers. His rage breaks out (baritone choir) racing with his grief (strings). Finally, he shuts himself down to all the sounds around, he made up his mind; first, feeling only grief, then slowly only the gentle blowing of the wind and then…
the next song begins :)