This air photo shows Sentinel Bay, on Garibaldi Lake, and the Sentinel Glacier on the top right.  The lake is at 4800 feet. The surrounding peaks are all around 7000 feet or higher. Lava flows around Mt. Price are quite noticeable at the bottom of the picture. Garibaldi Lake was formed when lava flows from Mt. Price blocked the valley, creating the 900 ft. deep lake.  It freezes every winter.  The barrier is somewhat unstable and it is not uncommon to hear chunks of basalt falling to the valley below.  The lake was stocked only once, many years ago, with Rainbow Trout.  Growing to about 16", they are the only resident fish.