Northeast China is among the most polluted snow-covered regions globally due to substantial anthropogenic black carbon (BC) emissions. BC particles, upon deposition, darken the snowpack and subsequently accelerate snowmelt and disrupt spring water resource availability. While the impact of BC in snow (BCS) on snowmelt is widely recognized, its competitive effect relative to climate warming has been less studied, a critical knowledge gap given Northeast China's heavy reliance on snowmelt for agricultural and residential water use. This study, utilizing comprehensive field measurements across Northeast China, reveals alarmingly high BCS concentrations with a mean of 1100 ± 810 ng g