Wires also caught fire -- with one of them falling next to an engine -- and a transformer blew shortly after the Scudder Street blaze broke out around 10 p.m.
A firefighter sustained a shoulder injury that was treated at the scene, Police Capt. Richard Uram said. No other injuries were reported, he said.
Flames consumed the first two floors of one home while quickly spreading.
A neighboring home caught fire roughly 15 minutes later, as frigid winds blew steadily at more than 20 miles an hour, with gusts of up to 40 mph.
PSE&G was called on a rush to kill arcing power lines.
Dead hydrants made things even tougher for firefighters dealing with temperatures that plunged into the mid-teens and a wind chill that made it feel much worse.
They still managed to knock the blaze down a little over an hour and a half after it began.
Firefighters re-entered the main building around 11:30 p.m. to complete searches and douse flame pockets. The fire was declared under control shortly before midnight, said Uram, the police captain.
The Red Cross provided temporary lodging, food and clothing. Strangers Helping Strangers also provided assistance.
The cause of the fire hadn't been determined, Uram said.
The Bergen County Prosecutor’s Arson Investigations Unit was summoned given the severity of the fire. The Bergen County Sheriff's Office sent a K-9 unit to search for possible victims and its Bureau of Criminal Identification to collect evidence.
Mutual aid responders included firefighters from Elmwood Park, Lodi, Maywood, Passaic, Rochelle Park, Saddle Brook and Wallington.
Click here to follow Daily Voice Northern Highlands and receive free news updates.