The Regional District of Okanagan-Similkameen issued the evacuation alert at 5:30 p.m. PT Sunday, around two hours after the wildfire was first reported after being spotted off White Lake Road, about five kilometres southwest of Okanagan Falls.
The 12 properties affected by the alert are on Yellowbrick and Willowbrook roads and homeowners were asked to be prepared to leave on short notice.
B.C. fire information officer Melissa Welsh says the fire, which is believed to have been sparked by human activity, quickly spread through grass, sagebrush and open timber with winds around 20 to 25 km/h early Sunday evening.
"This fire serves as a reminder to the public to be especially vigilant with their fire use or any spark-producing activity, as we are experiencing high to extreme fire conditions," she said in a written statement.
The fire had grown to 70 hectares and was completely uncontained as of 8:30 p.m., she said.
Five helicopters and 36 firefighters were brought in Sunday night to assist the Oliver, Kaleden and Willowbrook fire departments in establishing control lines.