Updated

An uncommon December tornado on Tuesday ripped off part of a hospital roof in a southwest Louisiana city, causing several patients to be evacuated, but no injuries.

The National Weather Service said the weak tornado touched down at 8:25 a.m., causing some property damage including at DeQuincy Memorial Hospital. Eight patients were transferred to hospitals in the nearby cities of Lake Charles and Kinder, but the emergency room remained open, administrative assistant Kashia Spears told the American Press (http://bit.ly/tDX2ws).

She said it's unclear when the hospital would be able to house people overnight again because the torn off portion of the roof covered a hallway of rooms for patients.

The weather service classified the storm as an EF-1 tornado, which can pack winds up to 110 mph, though an agency official said actual wind speeds were likely far lower. EF-1 tornadoes can have wind speeds as low as 86 mph.

The tornado was the first to strike anywhere in the U.S. this December, a month in which tornadoes are historically uncommon. Though last New Year's Eve, deadly twisters hit Arkansas, Illinois and Missouri. And wide swaths of Mississippi and Louisiana were under severe weather watches.

Weather service forecaster Todd Mogged said the DeQuincy tornado was likely on the ground for less than a minute. Though the weather service issued a tornado warning, Mogged said the fast-developing, short-lived twister probably touched down at about the same time as the alert.

Calcasieu Parish's emergency preparedness director Dick Gremillion said DeQuincy was fortunate.

"It's a miracle that there wasn't any more damage," Gremillion said. "It could have been a lot worse."

It was hospital nurse Alisha St. Germain's first encounter with a tornado. Her Chevrolet Tahoe sustained severe damage on its passenger side when roof fragments slammed into it.

"I just got out of my car about three minutes before it happened," said St. Germain, who bought the vehicle in September.

Beyond the hospital, damage was limited in the northern part of the city.

The tornado was part of a system bringing rain to several Southern states. Also, a different deadly storm that caused blizzard conditions in portions of the Great Plains weakened Tuesday as it headed east into Missouri and toward the Great Lakes.

In DeQuincy, Gremillion said recovery operations began minutes after the tornado passed, and by 1 p.m., workers at the hospital had begun installing a temporary roof in a bid to prevent further damage.

By nightfall, area utility companies said they had largely restored power after a day of widespread outages.