A snow plow operator called in the blaze.

A snow plow operator alerted emergency responders to the scene of a massive blaze at a restaurant in Metcalfe.

Early Monday morning, crews responded and declared a three alarm fire after flames and smoke ravaged the structure of the Main Street Grill and Pizzeria.

Firefighters said the front of the building collapsed, which make operations increasingly dangerous.

The restaurant was unoccupied at the time of the fire, and no injuries have been reported.

The fire was declared under control at 3:38 a.m.

The cause of the fire is under investigation.