Updated on Jan. 4, 2011:  Update: Investigators are looking several space heaters set in the void between the first and second floors of the Carriage Barn as the possible source of the blaze that destroyed the historic structure days before Christmas.

"The fire investigation is continuing, but we are focusing on three space heaters as the most probable cause," said State Fire Marshal Stephen D. Coan in a press release.

The joint investigation with Lenox Fire Chief Daniel Clifford found the three oil-filled heaters were being used to keep pipes from freezing; at least two were connected to extension cords. According to the release, "Investigators believe either one of the space heaters or one of the extension cords connected to a heater, may have overheated and started the fire."

The entire press release can be found here in pdf format.

Update on Dec. 23, 2010, 4:25 p.m.: Follow-up calls for more information on the blaze haven't been returned by Cranwell Resort but a statement was sent stating the resort planned on rebuilding the structure. The statement follows:

Original Post: 12-22-2010 04:37PM

LENOX, Mass. — A major structure fire destroyed the 120-year-old Carriage House on Wednesday afternoon at Cranwell Resort & Spa.

The smoke was discovered by a house inspector for the luxury resort at about 2 p.m., said General Manager Lewis M. Kiesler. "Fortunately, at this point, all the guest rooms in the Carriage House were vacant."

Kiesler was standing in the freezing temperatures calling guests to tell them their vacation plans were canceled as he watched a horde of firefighers from the surrounding towns battle the blaze. He said it was fortunate the Carriage House was at a distance from the other buildings on the sprawling estate.

The flames and smoke could be seen from the other side of Route 7 and billowed over the resort complex. The reporter at the scene said the wood-frame building looked like a tinderbox more than 45 minutes after the fire was reported.

Lenox firefighters called in mutual aid from neighboring towns, including Lee, Great Barrington, Stockbridge, Hinsdale, Richmond and Monterey. A second call for help brought in five more departments, including Adams and Clarksburg from North County, and set the high school as a staging area for more tankers.

The Carriage House was built the same year as the mansion, which now hosts dinner parties and banquets. It was linked to the spa with a glass-enclosed walkway and boasted 18 luxury rooms on two floors. The resort also has rooms in the mansion, a set of townhouses, three cottages and the Olmsted Mansion.

Kiesler said the resort was fully booked through New Year's Eve.

Great Barrington Deputy Fire Chief Edward G. McCormick, acting as public relations officer, gave an update shortly before 5 p.m.  He said the fire apparently began in the building's attic but fire officials would not speculate as to how it might have started.

It was reported to Lenox dispatch at about 2:30; the building was fully involved when firefighters arrived at the scene.

McCormick said 20 Berkshire County fire departments and one Connecticut department sent equipment and manpower to help fight the blaze.

The building's historic architecture made it difficult contain the fire; the partial collapse of one side of the building forced firefighters out of the interior.

No has been injured but the weather conditions were raising concerns over firefighters' safety, said McCormick, because of the amount of water icing up around the scene. 

"I think we'll be here until tomorrow morning," he said, as smoked continued to billow behind him.

Cranwell Resort posted this statement on its website shortly before 6:30 pm.

Today, Cranwell suffered an unfortunate fire to the historic Carriage House. Thankfully, no one was injured but the building is a complete loss. The building is isolated so it has not affected any other property at Cranwell. Please rest assured that the entire resort is open for business and you can continue your plans to visit. For further information about your room reservation, spa appointment or dinner reservation, please call 800-272-6935.

Staff writer Andy McKeever contributed to this report.

Firefighters can be seen battling the blaze from above; right, the 18-room building collapses.