In a normal winter, the Sierra Nevada, Pacific Northwest, and Rocky Mountains get hammered by systems that roll off the Pacific Ocean and drop hundreds of inches of snow. The summers, however, are sunny and dry, with only occasional precipitation related to the North American monsoon. Storms can be violent, but they are normally short-lived and an afternoon-only concern.

Bug pressure, meanwhile, requires action for about six weeks, plus/minus depending on the location, winter snowpack, and timing of the spring melt. Even when the mosquitoes are thick during the day, they are grounded at night by a light wind or temperatures below about 50 degrees.

The Desert Southwest sees even less precipitation and fewer bugs.

In such benign conditions, a backpacking shelter is rarely even needed. While I could continue to carry my modular double-wall tent as a just-in-case precaution, I instead opt for a lighter and more compact tarp and bivy system. This combination offers sufficient — albeit barebones — protections.

Gear List: Backpacking Tarp & Bivy System

My tarp & bivy system is the lightest and least expensive of my go-to backpacking shelter systems. The reason is simple: There is not much to it.

Critical: A must-have, no exceptions

Suggested: A valuable addition, few reasons not to bring

Optional: Not critical, but worth consideration

Contingent: Depends on trip objectives, conditions, and/or other selections

Unnecessary: Unlikely to need and/or can be improvised

Advantages

In addition to its weight and size, the primary reason I give up my tent is so that I can “cowboy camp,” or simply sleep under the stars in my bivy. This has a number of benefits. I:

Retain protection against insects and groundwater, and some wind.

Avoid having to set up and break down my shelter, which saves me time and an inconvenience

Pull into camp later and leave earlier, because I have less set up to do;

Camp where I would struggle to pitch a tent, like on a slickrock slab or under the tiny canopy of a krumholtz spruce.

Can move around more comfortably, because I’m not stuck inside a bug nest or fly.

Enjoy it, honestly.

Another oft-cited advantage of tarps is ventilation, which helps to reduce condensation. This is absolutely true, but it’s not a relevant perk in the arid Mountain West and Desert Southwest, where nighttime temperatures usually remain above the dew point.

Limitations

Let me just put it out there: For most backpackers, a tarp & bivy system is completely unappealing. It’s:

Not foolproof,

Not private,

Not full-sided, and,

Not for claustrophobics.

Furthermore, while the bivy is fully enclosed, there is no fully enclosed living area, as there is with a tent. For better or worse, with a tarp & bivy you feel more immersed in the wilderness.

If you are not turned off yet, then let’s discuss a few specific situations that are a struggle for the tarp & bivy:

Bug pressure

Technically, the bivy is bug proof. However, ‘skeeters can bite through the mesh where it’s flush with skin. Solutions:

Tie off the top of the bivy to a tarp or branch;

Wear a hat at night, so that the brim suspends the mesh off your face;

Cinch tightly the hood of your mummy bag, and let the mesh drape across it.

But even if the bugs can’t get at you, their high-pitched whine will keep you awake if they are inches from your ear drums.

I only use the tarp & bivy if I expect no or light bug pressure. I can handle a persistent mosquito or two, but I prefer other solutions for constant pressure.

Protected camps

Open-sided tarps are incompatible with wind. The photos that suggest otherwise are good candiates for Instagram.com/YouDidNotSleepThere. If they went through with it, I hope that the photo was worth a crappy night of sleep.

Some types of tarps can provide full-sided wind protection. But unless this need is the exception (not the norm), I would rather have a full-sided tent that is easier to pitch and that has a real door.

Applicability beyond the West

I have used a tarp & bivy in every ecosystem in North America. Without question, it excels most in the Mountain West and Desert Southwest, where nights are normally dry, calm, and bug-free. In other settings I’m not as enthusiastic about it.

Eastern woodlands

Nighttime temperatures do not drop drastically in the East, and mosquitoes buzz around all night during the summer. So at a minimum, I would swap the bivy for a tent-like nest such as the MSR Thru-Hiker Mesh House 2 or one from BearPaw Wilderness Designs, for more robust bug protection. This system would approach the weight of a lightweight tent, but it would be better ventilated and more versatile than most (because not all tents are modular). For example, the nest could be pitched inside of an AT shelter, or pitched by itself on dry nights.

Pacific Northwest

In the Pacific Northwest, I would be concerned about nighttime insect pressure at lower elevations (warm temperatures), as well as driving rain at higher elevations. The latter can be partially mitigated by an oversized tarp, such as the Rab Siltarp3, which is a giant 10’ x 12’, but I would tend to simply favor a full-sided modular tent.

I would be curious to hear thoughts from PNW specialists about the tarp & bivy system.

Tarps for group camping

Even if you end up with a different type of backpacking shelter (e.g. a tent or a hammock), do not give up on tarps in wet environments. They can be used to create a large protected space under which a group can gather in wet weather, rather than everyone being stuck in their individual shelters. A budget friendly option is the REI Camp Tarp, which is a 12-foot square and about $70. Oversized hammock tarps work extremely well, too.

Tarp discussion

Size

Unless you just want to impress other people in the forum with your UL gear list, avoid handkerchief-sized tarps like the Rab Element 1, which is just over 7 feet long and 3 feet wide.

When you actually need it, a small tarp will fail you: it offers minimal interior space, and the scantily protected head and foot will get wet from rain splatter and incoming rain.

A few extra ounces of fabric go a long way in increasing the space protected by a tarp. For example, the MLD Grace Duo weighs just 2.8 oz more than the Solo, but it’s 6 inches longer and 24-30 inches wider, enough space for a second person or to create a palace for one.

Shapes

Dedicated A-frame tarps have a pre-shaped catenary curved ridgeline that eliminates sag but hinders flexibility. I like them: they are simple and relatively easy to pitch. The two open ends are vulnerable to driving rain, but that can be offset with good campsite selection, an oversized tarp, and a low-to-the-ground pitch on the windward side.

Some A-frame tarps are tapered, whereby the head area is wider & taller than the foot area. Others like the Eagles Nest ProFly Sil Nylon Rain Tarp have a uniform width. Tarps with a taper make for better ground shelters, but symmetrical tarps can play double-duty in a hammock system.

Besides A-frames, other tarp shapes include:

Flat tarps like the Sea to Summit Escapist, which is 10’ x 10’. They are the most versatile, but also the least user-friendly because they have no natural shape.

A-frame tarps with optional “beaks” at the head and foot, like the Rab Element 2. These beaks improve storm-resistance but add weight, reduce ventilation, and limit pitch angles.

Poncho-tarps like the ZPacks Groundsheet-Poncho, which is best used as just-in-case shelter or rain gear, not regular use.

Bivy discussion

Top material

A bivy with an all-mesh top like the Borah Bug Bivy or Outdoor Research Bug Bivy will be cooler than a fabric top like the Mountain Laurel Designs Superlight or ZPacks Splash. That is an advantage in warmer temperatures, but a disadvantage in cooler and windier conditions.

Fabric tops must be made of highly breathable fabric. Avoid “coated” top fabrics, such as with the MSR E-Bivy, as well as any “waterproof-breathable” top fabrics, such as with the Black Diamond Twilight Bivy. Without adequate breathability, moisture (from insensible perspiration and drying clothing) will become trapped inside the system and condense when it reaches the bivy top, wetting your sleeping bag.

Side zip

Unless you want to squirm into your bivy each night, select at least a standard length zipper. It adds about a half-ounce versus a short one, big whoop dee doo.

Material quality

The primary purpose of my bivy is to keep the insects off me. The floor should be waterproof, but it need not be bomber since I always sleep on top of a waterproof ground sheet and since the ground is usually dry.

The water-resistance of the top fabric is not a concern of mine. I rely on an oversized tarp to keep away precip and splatter. Plus, I have no long-term faith in DWR treatments.

Alternatives

In addition to bug nests, mentioned earlier, another alternative to the bivy is to simply do without it. I would only recommend this if you are using a mummy bag, which is less drafty than a quilt, and if you are expecting no bug pressure, since your backup system would be a head net.

Ground sheet discussion

A ground sheet is optional in the tarp & bivy system, although I would generally recommend it, and strongly recommend it to bivy-less sleepers.

The ground sheet has a few roles:

A clean and dry space to lay gear;

Supplement the waterproofness of the bivy sack’s bottom; and,

Reduce abrasion between the air mattresses and the ground, and to blunt sharp objects like pine needles.

A popular groundsheet is Gossamer Gear Polycryo, because it’s cheap and ultralight. You can buy this material locally at hardware stores, in the form of window shrink map, but you must cut it to size.

My ground sheet preference is an emergency space blanket. It is comparable in expense, weight, and durability as Polycryo, but it is warmer because the Mylar reflects radiant heat.

Own a tarp & bivy? What’s your exact setup and what are your thoughts?

Considering a tarp & bivy? What are your top prospects or your reservations?