The first 911 call came into dispatchers at 6:18 Thursday evening.
A home on Red Chestnut was on fire, black smoke billowing through trees that line a cinder block retaining wall between the Sonora Hills community and Greenley Road.
More than a dozen calls followed as, across the street at Sonora Elementary School, parents and students attended back-to-school night.
The fire started in a garage and quickly engulfed the home at 22 Red Chestnut and spreading to the home next door, 20 Red Chestnut where firefighters halted further progress.
The occupants got out of the house, but one woman was taken to the hospital suffering from smoke inhalation, Sgt. Andrea Benson said.
Sonora Fire Department was first on scene, Chief Amie New said. Firefighters from four other departments followed quickly and put out the fire in the second structure before turning to the first.
The housing complex is located about two miles by road from downtown Sonora and about a mile as the crow flies, separated by the prominent hillside high above downtown.
Sonora Hills is an active living senior community with a clubhouse, pool and spa and walking trails near Adventist Health - Sonora, Sonora Elementary and the Adventist Health Pavilion.
The fire’s cause is not yet known, and Tuolumne County Fire Department is handling the investigation.
The first house was fully involved when firefighters arrived. A car parked between the homes was charred and various pieces of furniture smoldered and flared on the driveway.
As dusk settled in, firefighters used chainsaws and hand tools to locate and ventilate hot spots on the home where the fire is said to have started.
Crews were on scene late into the evening. On Friday caution tape surrounded the scene and piles of charred two-by-fours were stacked along the road.
Also responding were fire departments from Columbia, Cedar Ridge and Cal Fire.
New said the subdivision is not surrounded by wildland and there was little landscaping between the houses, which was fortunate in ensuring the fire did not grow.
New said the Sonora Fire Department caught a break just the day before when they were called to a residence on June Street in Knowles Hill near downtown and adjacent to an expanse of forest.
The house was full of smoke. Firefighters turned off all the utilities, which stopped the fire from progressing. The cause was found to be a faulty HVAC system.