Lake Louise is a glacial lake formed during the Holocene warming and deposition of a terminal moraine that acted as a dam for the meltwater during glacial retreat. The distinct U-Shaped valley seen in A-1 is a key feature of glacial valleys. The emerald green colour of the lake seen in A and B is due to suspended 'rock flour' in the water. Rock flour is fine silt and rock powder produced by the mechanical grinding of surrounding mountains during glacial retreat. These particles become suspended in the meltwater and reflect the surroundings. The icy debris fan seen in B-1 is an ice and sediment dominated landform constructed as a result of deglaciation as ice and debris accumulate at the base of the catchment.