(MCT) — NEW YORK — More than 200 patients were being evacuated from two Manhattan hospitals late Monday after backup power systems failed in the wake of Sandy, a massive storm that roared ashore in New Jersey, swamping New York, killing at least 12 people and wreaking havoc across a huge swath of the Northeast.

The backup generator failed at NYU Langone Medical Center, New York Mayor Michael R. Bloomberg said. Nearly 50 of the patients were described as “critical” and were being taken to the Mount Sinai Medical Center. A second New York facility, Bellevue Hospital Center, had a similar problem and had to evacuate, the New York Fire Department said.