On my recent hikes I've been using my bivy with no other weather protection. I bring a tarp just in case but on all my recent trips I've known that the chance of rain was slight. Snow would also not a problem. Last winter I went on a night when 8 inches of snow was predicted. I slept in the bivy with my frogg toggs rain jacket draped over my face. In the middle of the night I was awakened briefly by the soft sound of snow falling on the bivy. It was quite pleasant and so I just went back to sleep. In Missouri we don't have these snow storms that they have in the Rocky Mountains where feet of snow may fall accompanied by high winds. Snow fall in Missouri is gentle and accumulation is generally just a few inches. So a bivy and rain jacket is a perfectly adequate shelter.
The winter weather you worry about in Missouri is rain, or rain mixed with ice. This can be much more dangerous than snow storms because you can be wet through on a day where temperatures are hovering around freezing. And these storms are often accompanied by high winds. So I've been experimenting in the back yard to find a setup I would trust. The past few days there has been wind and freezing rain so I thought it was a good opportunity for a backyard test.
I've used tarps quite often of course but mostly with hammocks and that is a little easier because the tarp is tied to trees and the hammock holds you up close to the tarp so it's easy to get a very weather worthy setup. (In fact a hammock and tarp combination is the driest setup you can imagine. Brittany and I were out in hammocks on a night when it rained 8 inches during the night. In the morning the ground had become a swamp. Anyone in a tent would have been miserable because the water and mud would have risen high enough to get in. We were warm and dry all night.) On the ground it's potentially more difficult.
In my last blog entry I showed how I set up an A-frame pitch using my trekking poles and my Equinox 8x10 silnylon tarp. This is a pretty cool setup but since it is open on both ends you would have to face it 90 degrees to the wind to keep windblown rain from getting in. And with the broad side to the wind I'm not sure how it would stand up to strong winds. It might do better with two trees rather than trekking poles but that requires you to find two suitable trees. (Finding two trees the right distance apart in Missouri is easy, that's why hammocking is so convenient, but for ground sleeping you need two trees AND a flat space between them -- that combination is a little harder to find.)
Sgt Rock has great backing site in which he describes several tarp pitches. I choose to try the one he calls the Trapezoid pitch. He recommends it as a very weather-worthy pitch. You tie the middle of the 8 foot side to a tree and stake the opposite end out into the wind.
Then you stake the corners near the tree out.
The resulting space is quite sheltered and long enough to lie in.
I took my bivy and pad out and set them out under the tarp. I napped there for a bit during the rain and wind and it seems reasonable. There was a little spray on my face which I think was caused by turbulence around the the top of the tarp. But I didn't know whether it would be a problem. I could always drape my rain jacket over my head after all. To experiment I left the pad and bivy in place for the next 18 hours. Afterward there were chunks of ice stuck to the tarp but underneath it was quite dry. However the cumulative effect of the spray at the head end (which is the lee side) ended up being pretty substantial. So I'm not sure I like this. I'll need to think some more about how to handle that turbulence issue.
Part of the problem may be that my tarp is a flat tarp. Many ground sleepers who tarp use shaped tarps. There are many types of these but at the least you typically have a "beak" on the end so that the highest point is not open to the elements. This idea was first popularized by Ray Jardine, the father of ultralight backpacking in general and tarping in particular. Now you find beaks on many tarps.
Another area of concern is stakes. I use Gossamer Gear Tite-Lite titanium stakes. These stakes are lightweight but they have a problem or two. From the picture below you can see that they are rather dull in color. Not a problem up against the wood table in the picture. But imagine trying to find one in the woods after a gust of wind has yanked it out of the ground. About a year ago I was experimenting in my back yard and lost one this way. For all a know it's still there because I never found it.
In the picture you also see two products I was testing for adding some color to the stakes (titanium doesn't take paint well I'm told). One is reflective tape and the other is shrink tubing that electricians use (I don't know what they use it for).
The shrink tubing is really cool. You just cut a piece about an inch long,...
slip it over the head of your stake, and heat with a lighter (or some other heat source).
The result seems just as good as the reflective tape (can you tell which is which in the picture below?) because the colors are bright enough that they stand out well in nature. I've never lost one since I did this treatment.
But now that I'm experimenting with winter tarping I'm finding another problem. The ground in my backyard was frozen and getting the stakes in was a challenge. In fact when I pulled the stakes up I found that one of them was bent. It makes me wonder if I need a more robust set of stakes for winter conditions.