The Avalanche came down the first east fork of Tanners (fork is at about 8340fasl and about 0.73miles from the trail head). The trigger point elevation is unknown because it was out of sight. I passed the fork at around 5:45 to 6:00PM and reached 8900 and 0.90 miles from the trail head before turning around. I found down climbed and found a flat spot not far from there and took a short break. Took my crampons off and then headed down glissading off and on. I got to the fork at around 6:50PM and found the avalanche blocking my path. I traversed along the west side of the avalanche till the slope was relatively flat and crossed to the other side on the avalanche path (the east side) . It consisted mainly of ice boulders ranging in size from a diameter of 6 feet to less than one foot. The snow it traveled over was soft so it gouged 2 to 3 feet into it and created 3 to four foot snow moraines. The avalanche stopped about 500 to 600 feet below the fork.