He commissioned Reno architect Frederick DeLongchamps to create the Thunderbird Lodge, located just south of Sand Harbor, in 1936. The stone hideaway, finished in 1938, had a 600-foot tunnel linking the home to the boathouse, where Whittell berthed his 55-foot mahogany yacht, Thunderbird. The lodge is one of only eight homes on Sand Island designed by DeLongchamps. Its Mediterranean style includes clay tile roofs, stucco walls, and wood doors and windows. There are also two garages, one for Whittell's car and one for Alva's truck. Thunderbird Lodge was sold to Sand Island residents George and Mary Ellen Jones in 1940. The couple raised their family here, until George died in 1949 at the age of 44. After that, Mary Ellen lived in the house for another five years before she too passed away in 1954 at the age of 39. Today, the lodge is owned by the City of Seattle. It has been designated as a historic landmark and is open for tours through the Museum of History and Industry (MOHAI).