it was viola and perhaps the violent and public way her scheme had been carried out that caught the sheer force of the biting fervor of the crowd and the minute she became visible to onlookers , snowballs were hurled with such violence and quantity , her frame jerked with every missile that landed and it became clear very quickly that these projectiles had been prepared in advance and embedded with rocks or maybe worse as only snow would not rip through her coarse clothing or tear open her skin .