The PVA 9th Army suffered 19,202 combat casualties, and 28,954 non-combat casualties were attributed to the harsh Korean winter and lack of food. Total casualties thus amounted to 48,156 - about one third of its total strength. Outside of official channels, the estimation of Chinese casualties has been described as high as 60,000 by Patrick C. Roe, the chairman of Chosin Few Historical Committee, citing the number of replacements requested by 9th Army in the aftermath of the battle. Regardless of the varying estimates, historian Yan Xue of PLA National Defence University noted that the 9th Army was put out of action for three months. With the absence of 9th Army the Chinese order of battle in Korea was reduced to 18 infantry divisions by December 31, 1950, as opposed to the 30 infantry divisions present on November 16, 1950.