SANTIAGO - In one of the driest regions on earth, even a drizzle can cause an emergency. Less than 100th of an inch (about 0.2 millimetres) of rain fell on the Chilean port city of Iquique the other day, accompanied by moderate winds of about 10 mph (17 kph), according to the Chiles weather service, reported a private TV channel. But it was enough to knock out power to several neighbourhoods and to damage the roofs of 4,000 precarious dwellings, Governor Miguel Silva said late Tuesday. Schools were closed so that officials could repair the damage. There were no reports anyone was injured. The city of 170,000 people in northern Chile is in the heart of the barren Atacama Desert, squeezed between the Andes and the Pacific Ocean. It averages about 0.02 inch (0.6 millimetre) of rain a year, according to University of Chile meteorologists. Roofs in this region are to protect people from the sun, not from rain, Silva said.