Mrs. Snell is the mother of Sue Snell. She is a good-hearted woman, who doesn´t like Carrie´s mother, but tries to avoid confrontation and asks for forgiveness for her daughter´s actions. She also has positive memories of her prom night and likes the dresses that Carrie´s mother does for a living. That´s why they meet each other from time to time. She seems to like to watch TV.
In the alternate ending she, like in the 1976 movie, takes care of her daughter, who suffers, because of what happened.