Why is carnival season an ideal time for Montresor to carry out his plan?

During the carnival season everyone will be partying and drinking. This is a great opportunity for Montresor to let his servants skip out for the weekend and he can lure Fortunado into his "basement" --catacombs--to check out a cask of wine.  This wine is fictional, but he pretends to have such a cask and "has his doubts" about it.  By playing up to Fortunado's pride and the fact that he's a bit drunk, Montresor is able to talk him into coming over so he can kill him.  Everyone else will be busy and not notice thier disappearance.