Twenty-five people were killed after their bus veered off a slippery mountain road in the southwestern province of Guizhou on Tuesday morning, Xinhua quoted local work safety authority as saying. The latest investigation showed that a 51-seat bus, carrying 40 people, veered off an expressway in Zunyi County, Zunyi City and plunged into a 40-meter-deep valley at about 7:40 a.m., said a spokesman with the Guizhou Provincial Work Safety Administration. The crash also injured 14 others, two severely, the spokesman said. He said that only one person aboard the bus escaped injury. The administration earlier said that it was a 35-seat vehicle that had been carrying 38 people. An initial investigation blamed the tragedy on the unusual snowy weather in the region over recent days. The road was covered with a thick layer of ice and the temperature was about minus two degrees Celsius, a sharp contrast to the usual warm winter climate.