billowing voices

[KLPNO]

Hello everyone,
From the book Choose Your Story, Change Your Life by Kindra Hall.

Dorothy wound up in Oz because she ran away to escape her problems. She was looking for that perfect “somewhere over the rainbow.” A place where things went the way she wanted. Where she didn’t have to fear mean old neighbors or, as the story moved on, wicked witches.

But there are always fears. There will always be apple-throwing trees meant to discourage us or fields of flowers designed to put us to sleep. There will be billowing voices and final requests as impossible as securing the brooms of our enemies.

Does "billowing voices" mean loud voices?

 

[Rover_KE]

I doubt it, but 'bellowing voices' would.

 

[probus]

Cudgel my brains though I may, I cannot guess what the author intended "billowing voices" to mean.