A small town near Neverwinter that was destroyed by the eruption of Mount Hotenow in 1451 DR. The ruins were inhabited by ash zombies, malevolent spirits of those who couldn't escape the destruction, as well as twig blights that had flourished in the nutrient rich soil.
The druid Reidoth
had recently arrived in Thundertree to drive off the green dragon
Venomfang. Several members of the Cult of the Dragon had also come to
the ruined town, seeking to parley Venomfang's aid in their goals. The Heroes of Phandalin
defeated Venomfang after she to killed all the cultists
with her breath weapon. Reidoth led them from Thundertree to Cragmaw Castle as thanks.