Zane convinced me to post a comment about this tragedy.
With all the respect and sympathy to the families and friends I hope this never happens again. Unfortunately it probably will. We all know the risks we take in aviation to enjoy this beautiful backcountry, they died doing something they loved.
If this post sound preachy it's because I am sick and tired of too many of my friends or past students crashing in the backcountry. This will be number 8 for me. Please lets learn from this and not speculate as to the cause.
So you know where I am coming from. I taught for Norcal Aviation for 7 years. During that time I flew seaplanes an average of 800 hours a year in the Sierras. Its in my blood and I love it. I left a few years ago for my current job to fly airtankers for CALFIRE, though being based in Calaveras they are still my extended family. I did not know Ned the new owner but the student Mr. Cunningham was an ex-student of mine. Norcal has been in business for about 20 years now, with an incredible safety record and an unmatched reputation for high-altitude mountain seaplane training.
I have flown in and out of Cherry Lake hundreds of times in several different seaplanes that we owned. The C-150 did have an O-320. The maintainance was menticulous, it had to be. We ALWAYS let someone know where we were and exactly what time we would be back. The mentality we had in going into the canyons and lakes was that it was a "PRIVILEGE, not a given that we would land". You NEVER go up there thinking you will land. Think about this, if your plane only climbs a few hundred fpm its a rather small down draft to stop your climb at full power! Slightly more and you are going down, at full power! Any plane that we fly is not immune to this, I don't care if you have 350hp, mother nature will always win especially in the Sierras. You have to work WITH the conditions, not against them. I carry this mentality still to this day in my personal plane and my job.
Cherry Lake is a rather large lake for a mountain lake at 5000'MSL, one mile outside the border of Yosemite. The immediate surrounding terrain rises to 6-7000' with the lake in the middle of the bowl. The day was warm. A 150/150 on that day will climb out at about 300fpm with two people and minimal gear. I would never leave that lake unless I had circled the lake and climbed about 1500 feet minimum above the lake before leaving. Once I got stuck there and couldn't get off the water due to a high DA, calm winds, flat water. So you sit and wait. There are also specific areas you could climb in that bowl would give you 5-600fpm climb due to thermals. I usually had to use them to leave the lake.
This same situation could have happened to me several year ago leaving a different lake in the Sierras at the same altitude. After flying down the narrow canyon with a wind of only 10mph I was climbing out at 350fpm. After crossing over the dam at about 100 feet I started sinking about 200 fpm at full power and at Vy. That is only a 500fpm sink. I sucked the wing tight to the sunny canyon wall and waited for lift for over a mile. Had it not been that the terrain was descending at the same rate I would not be writing this.
No one knows exactly what happened, but this forum is a great way for pilots to learn from others, even in a situation as this. I think that is what makes this a tight knit group compared to other types of flying.