Towerfall, quite simply, lifted and knocked over huge stone structures, like castle towers, bridges, and city walls.
A variant of towerfall was stone fountain.
Inhil "Hurler-of-Stars" Lauthdryn, the Magister from 154 to 1294 DR, had a special love of blowing up castles, hence his creation of towerfall. He particularly enjoyed the spell, but he took its secrets to his grave in the Year of Deep Moon, 1294 DR.
- No mechanical information is given in the source.