The road from Ronda to Costa del Sol is closed to all traffic for six months.
The storm Jana caused severe damage to the critical artery that connects the Balcon de Ronda to the coast.
Andalucian officials hope to reopen a lane in four and a quarter months weather permitting.
The reconstruction project will include building a new €3.5 million viaduct.

Public Works Minister Rocio Díaz visited the affected area and confirmed that the magnitude of landslides has forced the total closure of the road between kilometres 11 and 37.
“Since the first moment, we have deployed all available resources, including drones and specialised teams for slopes,” Díaz stated.
The A-397 is a key route for connectivity in the Serranía de Ronda area, with daily traffic of 9,000 vehicles, half of which come from Ronda and nearby municipalities.
“We are aware of the impact this situation has on residents, and we will do everything possible to minimise it,” Díaz assured.
Drivers are advised to use extreme caution during heavy rains and to check road conditions prior travelling. Avoid unnecessary journeys until the situation has been brought under control.
Specialist climbing teams will begin the repair process by clearing loose stones from the hillside.
After that, they’ll secure the slope with a mesh of strong protection anchored into the mountainside and special barriers to catch any future rockslides.
The road stability is currently threatened by large boulders that weigh up to 400 tons.
The bridge is too badly damaged to be salvaged.
The Junta already has begun buying construction materials in preparation for when the weather conditions allow safe operations to commence.
A detour is not possible due to the terrain’s instability and complexity.