When someone is in a towering rage, it means they are extremely angry and possibly even on the brink of losing their temper. There are various synonyms for this phrase that can be used to describe such an intense state of fury. Some suitable options include being furious, livid, wrathful, enraged, boiling, seething, fuming, incensed, irate, or beside oneself with anger. Each of these terms conveys a different degree or style of anger, but they all describe a person who is in a highly agitated state and should probably be avoided until they calm down.