Don't become a victim this winter: Avoid letting vehicles 'puff' to warm up – Greeley Tribune
“Puffing” refers to vehicles left running and unattended — usually as they warm up. The nickname stems from the puff of the exhaust that can be seen during cold weather. Last year, Greeley Police Department Public Information Officer Kent Keller said Greeley experienced a 400% increase in car thefts during “puffing season,” compared to the warmer months prior.