Gary has been saying that he has wanted to see Crater Lake ever since he knew there was a Crater Lake. Even with that much anticipation, Crater Lake still overachieved. It is simply impossible to describe how blue this lake is.
So how was Crater Lake formed? About 7,700 hundred years ago there was a huge mountain standing here, probably over 12,000 feet high, or 6,000 feet higher than the level of the present lake. A giant pool of magma bubbled up underneath the mountain. It was not only venting out the top but also all around the walls of the mountain. Then there was an explosion estimated to have been 40 times greater than the 1980 explosion at Mount St Helens. The explosion blew out the top and through all the many vents down the mountain walls. The top of the mountain both exploded and collapsed back into the earth leaving behind a giant hole or caldera. Further flows of Magma sealed the floor of the caldera and also created what now is the island that you see in the pictures. Over the next several thousands of years the caldera filled with water from rainfalls and snow melt and made Crater Lake.
So why is Crater Lake so blue? One, the lake is very deep with its deepest point being nearly 2,000 feet below the surface. It is the deepest lake the United States. Two, the water is very clean and clear. There is no stream carrying sediment and pollutants into the Lake. It is all rain water and snow melt. The deep, clean, and clear water reflects back the blue light spectrum the way no other lake can.