Since she dropped off the 7-year-old pup at downtown doggy daycare Mutt Island on Tuesday, he's been out in the rain, and now some very cold temperatures.
Zenner said during his stay, Grizzy busted through the daycare's front door and took off running down the street.
They`ve only lived in the city a few months, so Grizzy may not know how to get home and out of the cold.
"He's an inside dog. He doesn't have the kind of coat that is protective for this kind of weather," she said.
Zenner has been searching streets, parking garages and animal shelters, and posting signs and even offering money, pleading for someone to bring him home.
She says she's not upset with daycare workers, but thinks they should fix the front door so dogs can't push it open.
Her only concern now is finding her best friend.
"It's driving me crazy," she said. "It's made it hard to be productive at work or at home. I'm just thinking about him. I can't stay out here 24-7 looking at nothing."