Layer buildup in the Arctic is a phenomenon caused by the accumulation of snow over time. This process is known as a snowpack, which is a layer of snow that has been compressed and hardened by the weight of additional snowfall. The snowpack can become very thick and dense, and can last for many years. This layered buildup of snow in the Arctic is an important part of the climate system, as it helps to regulate temperatures and affects the amount of sunlight that reaches the surface.