When was the event held that "Sieranevada" was selected to compete for the Palme d'Or at?
Sieranevada:  It was selected to compete for the Palme d'Or at the 2016 Cannes Film Festival. 2016 Cannes Film Festival: The 69th Cannes Film Festival was held from 11 to 22 May 2016.
from 11 to 22 May 2016