Arctic Priest( Frostburn, p. 46)
You can swap out prepared spells to cast spells to aid in exploring and surviving in frostfell areas.
Access to Cold or Winter cleric domain,
You can channel stored spell energy into spells that aid in exploring and surviving in the frostfell, even if you did not prepare these spells ahead of time. You can "lose" any prepared spell that is not a domain spell in order to cast any of the spells that appear on the list below, as long as the spell to be cast is of an equal or lower level to the one you lose. Spells you can spontaneously cast when using this feat include: control weather, create food and water, endure elements, heroes' feast, hibernate, protection from energy, and resist energy