She appeared in the episode Frozen Out.
Maureen grew up in a torn-apart home, with a sick mother and an uncaring stepfather. Her stepfather abandoned them on Christmas Eve; her mother died a few seconds later that night. Running away from a child services agent, she spent the night in the cold. She lived in the repair depot of the cable car company, with other homeless people, and occasionally came to Reverend Anderson for meals. When she was caught in the Big Bang, she gained the power to manipulate, and be impervious to, the cold. With her powers, she planned to ruin families, as her own family had been ruined.
A year or so after the Big Bang, her activities reached the news. She froze the power station on Dakota Hills, causing most of the city to black out. Static showed up, but after he had thawed out the power station, Permafrost attacked him. Static came out alive, but managed to anger her even more by ignoring her request for some change (which he regretted later on).
The following day, as she was begging in the Dakota Mall, her powers went haywire, causing a great panic among the shopping crowd. Panicking herself, she froze half the mall before Static arrived. Warding off the young hero, she fled into a clothes store. There, she broke down as she saw a mother protecting her daughter — showing the kind of love she lost years before. She fled, lamenting that she did not belong anywhere.
Permafrost met Static for the third time at the Dakota Turnpike, where her powers gridlocked Christmas traffic. Terrified of Static's imposing behavior, she fled after burying him in an avalanche of snow. Static chased her to her home in the repair depot, but found the place empty. Permafrost saw Static fly off with her most prized possession — a photograph of her mother. Now carrying a grudge against the hero, she attacked him at the tree lighting ceremony. After he warded off her assault, she calmed down when she heard him refer to her by her real name —Maureen —and offered help. After consolidating her grief, he brought her to Reverend Anderson. He offered her the services of the Church's homeless program, which she gratefully accepted.