"He just knew. I don't know. He just knew something was gonna happen," Denise Hatzis said.
When he started barking incessantly late Saturday night, Hatzis and her husband woke up and discovered a bad leak in their garage.
Minutes later they had moved their cars out, just in time for the roof to come crashing down.
The garage simply pancaked in on itself.
Fortunately, no one was in there at the time, but it was pretty scary for 10-year-old Nick.
"I thought it was an earthquake and the whole house was gonna fall down," he said.
Across Long Island, authorities are urging property owners to do whatever they can - as safely as they can - to clear their roofs as yet another winter storm heads our way.
At a Westbury fish packing plant, workers used seafood crates to dump snow onto an adjacent parking lot. They just had no place else to put it. Clearing the roof was hard work, they said. The snow was all across the roof. It came up to my knees.
"This is a problem. This is a very severe problem. The weight of the snow is crazy," building owner Roy Tuccillo said.
He ordered his employees to the roof after hearing about the Hatzis' near disaster back in Dix Hills.
The Hatzis said Hercules almost never barks. They don't know what moved him to wake them up, but nick says his best friend deserves thanks in the form of a million biscuits.
"I thought, 'Oh my God! We have the best dog,'" he said.