That mountain was the home of the Winter Warlock.
5 seconds sound clip from the Santa Claus Is Comin' to Town (1970) movie soundboard.
You can hear this line at 00:05:44.052 in the Blu-ray version of the movie.
Quote context
[...]
- Oh! The sleigh! It broke away. Oh, my goodness...!
- Where are you, baby Claus? Oh, do come back. Come back!
- Well, that strange wind blew the little sleigh right up to the Mountain of the Whispering Winds.
- That mountain was the home of the Winter Warlock.
- But the animals knew they had to hide that baby, and fast.
- They knew where that baby belonged.
- So, quick as they could, they started on their way.
[...]