I was just there three weeks ago trying to go cross country from Emeric Lake to Nelson Lake and then onto Matthes and Echo Lake before exiting via Cathedral Lakes. I went a little too far west under heavy tree cover and had to drop down to Echo Creek about 2 miles downstream of Nelson Lake. I could have corrected my course by backtracking to the northeast face of this 500 foot cliff, but because I met a very large mother bear and her cub while I was making my decision on where to start down, I decided it was best not to see them a second time that morning. That proved to be a wise decision, as a half hour later I heard the mating call of a male bear and met him when I was within 100 feet of the bottom. I didn't go upstream to Nelson Lake the next day because the number of downed trees and standing trees is high on both sides of Echo Creek and I wanted to try for Matthes and Echo Lake. This proved to be too difficult to do in a day, so I exited west to the Echo Creek Trail after going over a 300 foot ridge on the north side of Echo Creek (the branch coming out of Nelson Lake) and dropping back down on the other side into a valley with an unnamed creek that flows into the branch of Echo Creek coming from Echo Lake. This allowed me to pick up the Echo Creek Trail at least two miles farther to the north (and losing less altitude) than I would have been able to by following the branch of Echo Creek going out of Nelson Lake. It was also easier to get across the branch of Echo Creek coming from Echo Lake farther upstream.
The main problem you will have is climbing up over 500 feet after you leave Nelson Lake, cross over Echo Creek, and head south. There are no good places to do it farther downstream (it gets worse with more tall granite shelves and less dirt), and it will require great skill to do it where it is easiest. The first 100 feet of climbing will not be bad, but after that you will have a tough time picking your way around granite shelves and steep areas with loose dirt. On my way down, I ran into trouble three times where the grade was too steep to walk down anywhere safely, so I had to slide on my rear for 15 to 25 feet and then stop, get up, and continue on. You need to be an expert climber to attempt this safely, and I do recommend you go with someone equally experienced who can help with route finding and medical assistance if there is an injury. The tree cover is so heavy on the way up and at the top that you will never be found without an infrared sensor on a helicopter to direct a ground crew. There are very few places in Yosemite at this altitude that have as many tall trees as this area has.
Once you get to the top, which could take up to two hours, it's a nice forested walk south to Lake 9637, which is unnamed on most maps. Downed trees are everywhere, so you should anticipate your off trail progress will be slowed at least 25% over what your normal speed is on trail. Head to the south shore of this lake and climb up the pile of large rocks to the top where the three dead pine trees are. There were patches of snow when I went down it, but those should be gone now. The area around the lake was very swampy, but by now you shouldn't have to worry about sinking into the mud. There is a small pass when you get to the top by those three dead trees and you can drop down on the other side using a very long (1/2 mile) natural switchback that heads east and takes you to a runoff stream heading down the hill across lots of granite to Emeric Lake. I actually crossed over the runoff twice because switching back earlier would have meant dealing with swampy ground and big downed trees. You may find it easier to go that way now that the runoff is less. I was concerned about getting my leg caught or twisted in the mud and downed trees, so I chose the wet granite instead.
My experience camping along Echo Creek was mosquito free until the evening, but even then they were very light. However, camping even 500 feet away from Emeric Lake didn't help much, since the mosquitoes were very bad there all day long, but especially after 5 pm.
If you'd like to see some pictures of the area, let me know and I'll try to post some on Google. It looks much different than you might expect by studying maps or looking at it with Google Earth, which doesn't show the granite shelves in enough detail to do good trip planning.
ttiley is right about the hike from Tuolumne Meadows to Nelson Lake. When I did it a few years ago, I lost the trail on the way up with no snow around until the top. You basically need to head for the lowest pass that is southeast of Elizabeth Lake, which can be hard to see at times due to the heavy tree cover. I ended up going too far to the south and had to backtrack east a ways when I got near the top. The final 100 feet is a bit steep and may still have snow on it, but it is free of trees and is pretty much all granite. I was able to avoid all but one snow patch when I did it. Keep in mind that this moderately steep area is easier to negotiate than the 500 foot cliff south of Echo Creek.
Edited 1 time(s). Last edit at 08/06/2017 02:57PM by rgliebe.