Answer:
Snow line
Step-by-step explanation:
The lowest elevation at which layer of a permanent snow occurs in the summer is known as the snow line.
Snow line is defined as the boundary between a snow covered area and a snow free one.
The lowest level connotes with the level of snow during the summer because the temperature is warm at this period in time. Below this level, all the glaciers are frozen and will not melt in any way.
During winter, the snow line can rise due to drop in temperature.