Sept JMT Gear List

Actually, I think bivy sacks might be the perfect solution for you guys. They are warmer, will cut the wind and some spray. With that added layer by itself I think you might be fine with your bag and gear as is. Use with the tarp, but the breathable kind. If you get the un-zippable kind, like the zpacks ones, then you would be good in hotter weather as well.

"Is there any data on how much a bivy sack helps with warmth?"

I doubt it since there aren't any standards as to what a bivy sack really is.

I sewed my own two-person bivy sack over thirty years ago, and it used some substantial Goretex fabric. With it, I could sleep out in a snow storm without any problem.

However, now that we are within the ultralightweight context, we are looking at very thin fabrics. About all you expect to get is a little windproofness, a little breathability, and maybe a little rainproofness. Don't expect much extra warmth, although it might make a sleeping bag more comfortable because of the other factors.

The other thing is that a bivy sack gives you a place to stuff all sorts of things around your sleeping bag, and those help warmth as well. That would include any clothing not already worn, spare socks, towel, etc.

–B.G.–

"If you get the un-zippable kind, …"

zippable

un-zippable

hummmm……
;-)

In my experience the un-zippable ones are far superior to the zippable ones. ;-)

"In my experience the un-zippable ones are far superior to the zippable ones."

What? Do you just chew a hole in the side and then crawl through it?

I've made bivy sacks with a long zipper down the middle, with a long zipper down the side, with a short zipper across the chest, and with combinations. I've never had one that was un-zippable. Maybe you use buttons or velcro.

–B.G.–

Grammer police are everywhere.

"unzipp-able" then. Or is "unzippable" better.

Anyway, since they resemble a body bag I'm keenly interested the the ability to get out.

"Grammer police are everywhere."

Grammar police are out, but the spelling police are worse.

For the normal purpose of a body bag, they don't want the body to be able to get out.

–B.G.–

"Grammar police are out, but the spelling police are worse."

I think the location of a hyphen may still technically qualify as grammer. Humm, I guess that makes me the grammar police police.

"For the normal purpose of a body bag, they don't want the body to be able to get out."

My point exactly.

Now all someone has to do is mention Nazis and we will know this thread is over.

Whoops.

Just wanted to complain at the ignominious end to my wonderful thread…

(and show that I could spell "ignominious")

Well, your list is well thought out.

As far as the off topic of tarps goes, I always use a tarp for 3 seasons and do so in the shoulder season. As stated, good pitch is everything.

The other point to make is the old adage "hike high, camp low". If you plan on camping right below passes or in real exposed areas every day then it can be a problem. You can miss a lot of weather by just camping a bit lower and a bit more protected.

Site selection is king.