Pruina Tempestatis is an Elder Wand-exclusive spell that freezes all players in its radius. It inflicts the same status effect as Glacius, as well extremely low damage. The freezing effect can be undone through the use of either Incendio or Diffindo, with the former having the side effect of further burning and damaging the target even more.
Though not as frequently used as its more deadly counterpart, Infernum, Pruina Tempestatis is still effective at crowd control, since this spell's area of effect freezing capability can instantly suppress entire groups of players in one cast without killing (or even severely harming) the victims.
The words "Pruina Tempestatis" are Latin for "frost weather."