Why is the lake blue ?

Bow Summit是這次旅行裡，號稱最藍的一個湖泊，旁邊還有架設解說牌，來說明為什麼湖水是藍色的，以下附上原文，和自己的翻譯

The junction of the stream, the lake and the delta is the clue.Water leaving the glacier is muddy with rocks, gravel and silt. As the stream slows down most of that rubble is left behind to become delta. Slit flow into the icy water where most of it sinks to the bottom. Fine particles of the rock ground to the texture of baking flour remain suspended in the water.This "rock flour" scatters the blue - green rays of light, giving the lakes its special colour.

透過河流、湖泊與三角州的交接處可一窺究竟，冰河融化的水因夾雜著石礫與淤泥而泥濘不堪，當河流變緩慢，碎石會淤積並形成三角洲，淤泥流進冰水裡頭，絕大部份沉積至底部，被水研磨到像麵粉般的岩石顆粒會懸浮在水中，岩石粉末可以散射光線裡的藍綠光，並造成湖水特別的顏色。