by Ryan Jordan | 2003-09-03 03:00:00-06
The biggest gripes I hear from tent-tethered hikers about tarps are:
Most seasoned ultralight backpackers admit to #1 but choose to invest weight where it counts the most – as high fill down in a sleeping bag.
Most have also figured out a variety of solutions to #2, ranging from the spartan’s choice – a headnet – to the more secure and roomier offerings of “nest”-like shrouds of noseeum mesh such as those offered by GoLite; or a mesh perimeter sewn to the edge of the tarp as in Henry Shire’s TarpTent. Combined with some strategically applied DEET and/or permithrin, avoiding insanity from buzzing is not difficult.
Thus, the first two proclaimed disadvantages of tarp camping for three-season backpacking are weak arguments.
However, when it comes to #3, too many veterans – even experienced lightweight hikers – scamper down to the tree line to avoid having to face the rock music of tarp camping in a tempest. And, hey, I’ll admit it – when I’m carrying a poncho and leaving my tent at home, pitching a bombproof tarp in a gale force storm at 11,000 feet is not high on my list of things to do when dusk is approaching and I’m craving my evening soup.
However, being able to pitch your tarp properly under inclement conditions such as these is a skill that opens up new avenues of very light high mountain travel – including alpinism, ridge hiking, and alpine high routes. Above the treeline, you are immersed into a mountain range’s full glory – and sometimes, her wrath – en route to a richer experience with better-than-IMAX views, planetarium-quality stargazing, and an intimacy with the alpine realm that cannot be appreciated by spending the night in the arbor cathedrals of lower elevations.
And so, this article will focus on more advanced considerations for tarp camping above the treeline in inclement weather.
The two biggest mistakes novice lightweight mountain travelers make when tarping above the treeline is thinking that a larger tarp provides better weather protection, and that stakes and guylines provide opportunities for weight savings.
Consider two tarps, side by side. One measures 10’ x 12’ and the other 5’ x 8’, both staked as A-frames in similar configurations, with each corner staked to the ground, broadside to a stiff wind. Now consider the rule that deflection of the normal surface of a panel in tension is proportional to (1) the surface area of the panel, and (2) the degree of tension in the panel, and you can begin to appreciate the two most important factors that go into properly pitching a shelter in inclement conditions.
First let’s consider the surface area of the panel. A larger surface exposed to wind will deflect more in response to wind than a smaller surface exposed, given that tension across both surfaces is the same. Conclusion: use a smaller tarp if you are going to be exposed to high winds. If you don’t buy into this philosophy, then consider that the world’s strongest mountain tents are those that (1) have the smallest sized panels (visualize a geodesic dome tent with eight criss-crossing poles vs. only two or four), or (2) are low in height, width, and length (like the Integral Designs MK1XL, the de facto standard of blizzard-ready mountain tents).
Small Tarps for Inclement Weather. The SpinTarp X, an ultralight silicone-coated 4.25’ x 7.75’ tarp by Bozeman Mountain Works (4.15 ounces) is designed to be used in conjunction with a bivy sack to provide overhead rain protection. Combined with plenty of tent stakes and guylines, it is well-suited to exposed conditions above the treeline.
Second, let’s consider the tension in the panel. Since we don’t have the option of using tent poles to reduce panel tension, we are simply left with stakes and guylines. As you add stakes (and guylines) to the sides of your tarp, you are effectively creating more and more (smaller) tension panels in the structure. The result: higher tension forces across the panel (resulting from smaller panel surface area). Stakes and guylines don’t weigh much – a set of 12 titanium skewer stakes and a set of Spectra guylines can weigh less than 3.25 ounces, while providing the structural integrity to your tarp required for weathering storms above the treeline. Conclusion: don’t skimp on stakes and guylines if you are going to be exposed to high winds.
High Uintas, UT: This tarp is actually two Integral Design Sil Ponchos, snapped together to form the ridgeline of a tarp pitch 8’ in length and 10’ in width, with its low end into the wind, which spilled down from a 12,000-foot ridge during the night. Panel tension and a tight pitch were maintained by using a total of 14 titanium skewer stakes and fine-diameter guylines.
We’ve addressed the need to deal with high winds already, but what about precipitation? Using a smaller tarp means a greater risk of getting wet from sideways blowing rain, snow, or spindrift.
Pitching windward edges close to the ground is one way to minimize the effects of wind and windblown precipitation on your sleep system. “Beaks,” such as those found on the front of Shires’ TarpTents, and the ends of the GoLite Cave series of tarps, also help. However, swirling winds that change direction often are the high-mountain norm, and tarp design and pitching options can only take you so far.
The mainstream mountain tarp aficionado recognizes these limitations, and often complements the tarp with a synthetic sleeping bag, a down bag with a nearly waterproof-breathable shell (e.g., Gore DryLoft or Pertex Endurance), or a waterproof-breathable bivy sack. There are a few problems with these sometimes futile attempts at making your gear work together, however:
Thus, I’m a strong advocate of bivy sacks that have a waterproof bottom (so you can leave a ground cloth at home) but with a highly breathable, water-resistant top (so they can effectively pass perspired moisture vapor quickly). An uncompromised DWR finish for the bivy top is a must so that precipitation can bead up on the fabric and roll off without penetrating into the rest of the sleep system. I’ve been successfully using bivy sacks with Pertex Microlight, Pertex Quantum, and Nextec Epic Malibu tops for nearly three years with great success in terrible weather. This approach works especially well in the winter, when condensation retained inside a Gore-Tex bivy sack can cripple your sleep system in a matter of only a day or two.
Breathable Bivy. A breathable bivy sack, like this 7.5-ounce (6.5 ounce without the zip-out noseeum mesh window) Pertex Quantum-and-silnylon bivy sack from Bozeman Mountain Works, can add significant warmth in windy conditions, and excellent water protection from wind-driven rain. Other possibilities to check out include the Oware Epic bivy, the Bibler Winter Bivy, and the Equinox Nylon Bivy.
Another benefit of a bivy sack (not unique to those with breathable tops) are additional warmth due to the entrapment of insulating air between the bivy sack and the sleeping bag (improves resistance to conductive heat loss), additional warmth due to inhibited exchange of warm with cool air inside the bivy (improves convective heat loss due to the bellows effect of air exchange), and the additional warmth afforded by wind resistance from the bivy sack (improves convective heat loss by maintaining boundary layer thickness through which the inside-outside temperature gradient is defined).
Staying Warmer with a Bivy. This photo was taken the morning after a subfreezing night in the High Uintas with winds in excess of 40 mph. The solution was simply to pitch the tarp (an Integral Designs Sil Poncho) low enough to spill wind effectively with plenty of stakes and guylines to maintain panel tension. The bivy sack, with a Pertex Quantum top (6.5 oz), was essential to staying warm in conjunction with an ultralight, 16 ounce down sleeping bag.
Arguments against such a system are that a bivy is heavier, and the weight is better spent on a warmer sleeping bag (also consider that a warmer down bag that is wet is not only not all that warm, but also heavier!). Epic Malibu bivy sacks weigh in the range of 9-12 ounces, while Pertex Microlight bivies range from 8-10 ounces. The recent release of Bozeman Mountain Works’ “X” Bivy (silnylon floor and Pertex Quantum bottom) reduces the weight to 6.5 ounces. This almost closes the gap between bivy sacks and ground sheets (remember that ½ of that bivy weight is a groundsheet you’d take anyway). The bottom line: a sub-12 ounce, breathable bivy sack affords tremendous wind and rain protection that cannot be provided by adding insulation (like down fill) to a sleep system.
Pitching a tarp above the treeline requires a bit of innovation at times. Trekking poles give you the opportunity to strike camp virtually anywhere, because they provide you with strong supports for the ridgeline. Those who do not use trekking poles sometimes carry dedicated collapsible “tent” poles (the ultralighter’s choice: carbon fiber poles from Fibraplex), and as often, take advantage of natural features such as sticks, large boulders, or existing equipment, such as ice axes, to rig the ridgeline.
Tent stakes for alpine camping should be thin, strong, and short. They need to be thin because the alpine realm is a rocky place and thin stakes snake their way through rocky ground better than thick ones. Stakes should be strong for the same reason – they need to resist a bit of driving force into the ground as the point deflects off rocks. Finally, they should be short (and thus, light and easy to place and remove) – six inches is plenty. My recommendation: titanium skewer style stakes 1/8” in diameter. There are stronger stakes (including those made with high strength aluminum in tube, T-, or V-shaped cross sections) offered by other companies, but they are heavier (0.5 oz or more each). The difference between a set of 12 1/8” x 6” skewer type titanium stakes (0.25 oz ea) and the latter is 3 ounces – significant when you consider that this could be an extra 3 extra ounces of down fill in your sleeping bag (which can boost its rating by 5 or 10 degrees) or 375 calories of extra food energy. Furthermore, the T- and V-shaped stakes are very difficult – and painful – to place and remove with bare hands in hard ground.
Guylines for tarp camping should be strong, light, short, and plentiful.
I’ve tarp camped with other ultralighters that use fishing line or dental floss for their guylines. I’ve also watched the slightest breeze snap these guylines, and I wouldn’t trust them above the treeline. Search for guylines that have very high strength:weight ratios. Those made with pure Spectra (such as AirCore) or Spectra cores with nylon sheaths (such as Kelty TripTease) make great guylines for fiercely windy conditions.
Guyline Creativity. This picture shows the kind of innovation needed to optimize tarp performance in high winds. Here, a single long guyline is threaded through each of the tarp’s side guyline tie-outs, with a series of six tent stakes securing apex points along the guyline. By adding only a single additional tent stake along each side, you are able to distribute panel tension across more panels, resulting in a tauter, more wind-resistant pitch.
Guylines can be pre-tied with overhand, figure-eight, or bowline loops in each end. They should be about two or three feet in length (which minimizes tangling during storage). Longer guylines can be made by girth hitching multiple short pieces together. This gives you a very flexible system for pitching in a variety of configurations. Once your guyline length is set, simply girth hitch one end loop to the tarp’s guyline tie-outs, insert the stake in the other end loop, tension the guyline, and set the stake. Tension is adjusted by resetting the stake, rather than fiddling around with a tautline hitch, that artistic adjustable knot so prominently showcased by the Boy Scouts as an essential skill. This is where the benefit of titanium skewer stakes really shines – since they are so easy to place and remove relative to other types of stakes, this guyline-and-stake system used for tarp adjustment is simple, fast, and effective.
This article focused on three key points:
Tarp camping above the treeline in inclement weather is not an essential skill for the average backpacker. However, for the lightweight hiker that likes to travel above the treeline for long distances, having the flexibility to pitch a camp anywhere you like, and knowing that you are going to have a shelter and sleep system that can handle high winds and driving rain, opens up new possibilities in your backcountry explorations. With this skill you’ll achieve a level of intimacy with the mountains that cannot be enjoyed from beneath a canopy of trees.
Titanium Skewer Stakes
Breathable Bivy Sacks
"Advanced Tarp Camping Techniques for Inclement Conditions," by Ryan Jordan. BackpackingLight.com (ISSN 1537-0364).
http://backpackinglight.com/cgi-bin/backpackinglight/00150.html, 2003-09-03 03:00:00-06.