Was the hole in a St. Paul alley a giant pothole? A sinkhole?

Technically, it was neither, but it was big enough to require three tow trucks to haul a recycling truck out of a Merriam Park alley on Monday afternoon.

“Our driver was collecting in the alley and essentially the ground underneath him collapsed in on itself,” said Kate Davenport, co-president of Eureka Recycling. “… After it happened, he knew what was going on, but in the moment I imagine it was rather disturbing.”

The hole is estimated to be 7 feet by 4 feet, and nearly 3 feet deep, according to Lisa Hiebert, St. Paul Public Works spokeswoman.

Terry North, of St. Paul, was passing by on Monday when he saw the truck that was stuck in the alley in the Portland and Fairview avenues area.

“I was in awe,” said North, who posted about it on Facebook. “I was concerned that it was going to tip and sink farther into the hole.”

The recycling truck’s back wheel collapsed into the hole shortly after 1 p.m. Monday, Davenport said. It was towed directly to their mechanics shop to determine the amount of damage.

Workers responded and blocked off an end of the alley, Hiebert said. Public Works’ sewers division will excavate on Tuesday to try to determine the cause.

They’re looking into whether an abandoned sewer could have caused the asphalt to collapse, Hiebert said.

Although people might call it a sinkhole, that’s a geological term for when sandstone, limestone or other rock gives in, usually from erosion, Hiebert said.

North said he was looking around at the condition of the city’s roads after he saw what happened to the truck.

“My vehicle has taken a pounding on the roads this year more than normal it feels,” he said.