The fire broke out in attic of the home in the 3800 block of East Mercer Way just before 10 a.m.

"At one point there were just 50 foot flames shooting up for 15 minutes," said witness Fred McFall, who watched nervously watched as crews attacked the flames that came within inches of his sister's home.

"There were no hoses going on her house," he said. "They're out of town. I was really afraid that her house was going to catch on fire."

Fire officials said the blaze started in the attic around 9:30, and was not related to fireworks.

Firefighters from three departments responded to help control the fire. They had to maneuver through narrow, windy roads and backyards filled with brush to reach the burning home.

"When crews have to stage up on a road like this, it takes extra time to gather equipment and walk down to the area where you're operating," said Dep. Chief Steve Heitman with the Mercer Island Fire Department.

When firefighters first arrived, flames were leaping from the roof of the large house and the dark smoke could be seen throughout the Eastside.

A woman and her son were inside the home when the fire started, but they ran outside and called 911 when they heard smoke detectors going off. Both of them made it out safely. No one was injured in the blaze, officials said.

According to the real estate Web site zillow.com, the 7,390-square-foot home is worth nearly $6.7 million..

King County Assessor records say the home is owned by Kurt Dammeier, who owns Beecher's Handmade Cheese at Pike Place Market and Pasta and Co. restaurants in the greater Seattle area. He's also a director at Pyramid Breweries.

Investigators said it will take at least 24 hours to determine the cause of the fire. It is not known whether there were sprinklers inside the house.

YouNews contributor hunbun736 captured this video of the fire: