The buzzing sound of the first drone prompted the BBC's crew to take cover under bushes beside the road in the mountains south-west of Taiz. Climbing back into the vehicle and driving away, they heard the loud thuds of strikes about 10 minutes later, though it was unclear where they landed.
Pro-government forces, backed by a Saudi-led coalition, are battling to halt the Houthi advance that began in early September and has escalated Yemen's civil war. The Houthis swept down the coast, taking control of the Bab al-Mandab strait, a vital passage for global shipping.
Homes scattered across the slopes near the front line stand abandoned after families fled. Ali, a resident living about one kilometre from the fighting, said: "Two mortars landed here on my property." He sat outside with a herd of goats as the sounds of incoming and outgoing fire punctuated the silence.
The front line itself is indistinct, the BBC reported, with no clear sign of where government control ends and no man's land begins. Soldiers manning checkpoints guided the crew through to the edge of territory still held by government forces.
The conflict, which has ground on for years, has flared again with the Houthi offensive that has redrawn the map of western Yemen. The Houthis already control the capital Sanaa and large areas of the country's north and west. Their latest gains threaten the internationally recognised government's remaining footholds.