Dragon's breath additional effects

[Nalistar]

Hi, I'm about to use an ancient white dragon in the next session of the game I'm DMing and after reading the Blizzard effect of its breath weapon I couldn't understand how it exactly works.

Does the effect add up on top of the damage the breath weapon would normally do or instead of it? I've read the entries for other dragons' breath additional effects and couldn't figure a definitive answer.

Thanks for the help

[RumpinRufus]

I think it replaces the normal breath weapon (but takes a "use" so it needs to recharge before using the regular breath weapon again.)

[Bane Wraith]

It seems to function as a simple standard action. The breath weapon damage would not be added to it; it's merely the medium that this ability uses. Chromatic White Dragons don't seem limited in their breath weapon use either, so there's no issue of "recharging".

[Nalistar]

Thanks guys