Fresh snow made the course sticky and reduced visibility, but Rebensburg prevailed with a time of 1 minute, 16.45 seconds, 0.33 seconds ahead of Austrian Nicole Schmidhofer.
The win moved the 23-year-old Rebensburg into fifth place in the overall World Cup standings.
"We are kind of used to it," Rebensburg said. "We train a lot in those kind of conditions. I was so focused today that I didn't get disturbed."
Tina Maze of Slovenia, the overall World Cup points leader, was third just 0.01 seconds behind Schmidhofer. "It was a hard battle," Maze said. "I couldn't see anything; my goggles were covered in snow."