Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board Bivy use in the Sierra?

What bivy bags do you guys use for the summer? How do you like it? I'm mainly worried about condensation.

I remember it being pretty dry out there, but I still don't know if a bivy would work well for summer temps.

Since the far majority of the nights are clear, I thought I would use a bivy sack to keep moisture off of me, block some wind, and keep the mosquitpos off me (important!). For the rare rainy nights, I would use a small tarp, so the bivy would also help there too.

Thanks!

Depends on the time of year and the weather. Let me expand on the weather as it seems like a silly statement. In August and sometimes in September tropical storms can come up the Sea of Cortez and then up the Kern River valley. If you hit one of those RARE events you can be in drizzling/pouring rain for three to four days. I have experienced it back in the '80s. Like I said it is very rare but watch the weather especially if it's coming from the South and don't rule it out.

Most of the time it's just the afternoon buildup of moisture due to the orographic lift and it's just afternoon thundershowers coming from the West. Then the nights are usually clear in the summer. If the clouds aren't forming real well by 10am then usually there won't be enough for thunderstorms.

I spend most of my time with just a poncho and ground cloth, and a bivy bag in the late fall. The bag helps with the extra warmth.

All this being said be sure and know the forecast and don't think that everything will pass you by. There are certain microclimates like around Whitney where it seems to me to have more thunderstorms than to the south around Langley.

Take what you feel comfortable with and remember that a tent, especially with two people sharing isn't that heavy and is a lot warmer than radiating heat to the stars.

If you really hit mosquito season after first melt, then you will not be able to sleep without a tent. Later in the year mosquitos aren't really that bad but they will wake you at dawn on many occasions unless your bivy is 100% mosquitoproof. Ripstop tape can help on zipper closures, but the buzzing can be unsettling.

I always carry a tent in my car and make the decision after looking at the weather forcast at the ranger station.

I second the mosquito concern. In mos season I always bring a tent. Otherwise, like FBT I bring a tent and a bivy sack and decide at the trailhead what to carry up.

Generally speaking, if there's any chance of a significant t-storm, I bring the tent.

sometimes I carry a bivy and sometimes I carry a tent. The bivy I'm using these days has a hoop over my head and that's kind of nice - it's an Integral Designs Unishelter made with eVent fabric - no problems with condensation.

http://www.integraldesigns.com/product_d...producttypeid=1

There's really no need to carry a tarp along with a bivy.

Thanks, info about condensation is what I was hoping for.

For the record, I'm looking at a 7oz water resistant bivy and a 9oz tarp. The idea is that I will sleep out every night I can in the bivy and only use the tarp for rain.

So, the bivy should protect from dew, light splash back from a tiny tarp, and keep the mosquitos off me. The tarp should just keep the rain off me.

Your bivy is nice and light but you can go a lot lighter on the tarp. Consider http://www.gossamergear.com/cgi-bin/gossamergear/polycryo_ground_cloth.html which weighs a whopping 1.5 ounces and will set you back just $6.00. It looks terribly flimsy, but it isn't.

Brent

I have one of those (well, two) that I use as a groundcloth. I really like them. I won't be taking them with me if I have a bivy though. I'll be using the tarp (oware cat tarp) for shelter from the heavy rain, which I doubt I will even encounter. Gotta have a solid shelter though.