With cold weather still lingering, authorities are issuing this warning:  Don't leave your car running with the keys inside.  It often leads to your car getting stolen.

That’s called “puffing” and in some places, like Colorado, it’s actually against the law.

Monday, Grand Valley authorities kicked off Puffer Awareness Week.

It’s a statewide effort to put the brakes on "puffers" - a term coined by car thieves.

Authorities will be on the lookout, and will provide educational information to those caught "puffing."

The goal is to educate people about the law, so that their vehicles become less attractive to thieves.   

“We want to try to do what we can to reduce the number of auto thefts here in Mesa County,” Sergeant Douglas Norcross, with GJPD, said. “We’re hoping that the community will help us out by not leaving their vehicles running unattended.”

Across Colorado, about 50-percent of auto thefts involved cars left unattended while running.