Fire chief Colin McKenna said he initially thought to look for a damaged power pole, owing the severity of the damage.
Ms Harrison said it was the one morning she had decided to drive to work, rather than take the train.
She said she had slowed down as she reached the 70km/h zone into Featherston when the dog had run across the road.
"I couldn't do anything, it happened so fast."
The Times-Age spoke to the dog's owner, who was distraught and said she had lost "her best friend".
She did not wish to comment further.
Police advised Ms Harrison it was unlikely to be a police matter and up to her insurance company to process.