The disruption to the Weave caused by this ritual reacted violently to users of silver fire, causing them to be hurt badly every moment they spent within the ritual's radius.
The closer one got to the source of the ritual, the worse its effects became, with the worst being a dead-magic zone that allowed the Shadow Weave to still function.
It has only been recorded as being used once. In the second battle for Shadowdale between the Army of Darkhope and Shadowdale's defenders, Sharran allies of the Zhentarim began the ritual and sealed the defenders' fate. Without full access to the Weave, the defenders were even more easily outmatched. Eventually, however, adventurers disrupted the ritual and Syluné Silverhand expended all of her energy to reverse the process, destroying herself as a result.