The Great Caldera

Tonight I thought I would give you a little history on Aniakchak and my impressions as I landed on Surprise Lake in the caldera. Aniakchak was formed when a 7,000 foot mountain collapsed, leaving a six foot wide, two thousand foot caldera. It is estamated that 3,500 years ago a large explosion caused the loss of 3,000 feet of the upper part of a mountain. The remainder of the mountain collapsed leaving an ash filled, flat bowl. Since then many lesser explosions have left cinder cones, lava, and explosion pits on the floor of the caldera. The last recent explosion came in 1931. Though it was considered a small explosion, it left ash scattered through out the caldera and in villages up to 40 miles away.

Surprise Lake was probably a large snow filled lake that eventually began to spill out of the crater, eroding the wall until the Aniakchak river was formed. The area where the water leaves the crator is called the gates. They are high walls of rock, ash, and fossils that are quite impressive. Surprise Lake now lies in part of the caldera with hot springs feeding the lake along with melting snow and lots of rain.

I finally left for Aniakchak at 7 pm on the 10th of August. Because of cloud cover half way between King Salmon and our destination we flew high over the clouds. The first team was in the caldera and reported that they had clear skies, so the plan was to fly high over the cloud bank then entered the clear skies right into the caldera. The trip out was kind of boring as all you could see were clouds. Then after an hour mountain peaks rose above the clouds. They were snow covered and quite impressive. Mount Aniakchak was one of them. Minutes later the plane dropped into an unbelievable sight. The lake was a silvery blue and at one end a pool of orange and yellow drifted into the lake. The caldera was lit up by the snow covered mountains around the rim and the glaciers that rested on them. I knew right there I was going to love this place.