St. Paul police are asking residents not to leave their cars running and unattended after 33 vehicles left to warm up were stolen off city streets this month alone.

The crime of opportunity has gotten worse as temperatures plummet. In the past three days, 10 cars that were left running were stolen. Three of those thefts occurred Friday.

“This is how brazen some of these thieves are,” said police spokesman Steve Linders. “One of these victims started his wife’s car and got into his car, which was sitting there, and somebody jumped in his wife’s car and drove away with it.”

The theft occurred about 6 a.m. on Dec. 10 in the 500 block of Hoyt Avenue.

The man drove after the car thief, who bailed out of the vehicle a few blocks later. The two men scuffled, and the suspect fled before police arrived.

It’s not uncommon for many victims to witness the thefts, police said.

“We’ve had cases where people are standing at their front doors looking at their cars and they watch somebody jump in and drive away,” Linders said. “It happens that quickly.”

On Thursday, a woman spotted a vacant 2008 Nissan Sentra running in a rear alley parking lot in the 600 block of Lawson Avenue, police say. The car’s driver, who had the vehicle on loan from his religious organization, had gone back inside for a minute when the car was taken around 8:34 a.m.

“It can happen in an instant, and it can ruin your day,” Linders said.

The car was later found parked outside the ticketing and drop-off section of the Minneapolis-St. Paul International Airport. Video surveillance captured images of the woman “running” from the car to a boarding gate inside, Linders said.

Metropolitan Airports Commission spokeswoman Melissa Scovronski confirmed that the woman that St. Paul police believe took the car was arrested inside security at Gate E2 around 10:05 a.m.

Police said they do not know where the woman was intending to go.

Many thieves are striking simply because the opportunity is there, Linders said. Most take the cars to get from one point to another and then abandon the vehicle, although some cars are sold for parts.

Some vehicles are never recovered, Linders said, while others are found damaged.

“I think the lesson is, spend a couple of minutes with your car warming it up instead of your whole day without it,” he said.