When you go out and buy a tent, no matter the manufacturer, it typically comes with an integrated rainfly, and you often can also pick up a ground cloth to match the tent's footprint. So why not consider an integrated layering system when shopping for outerwear?

Think of it: clothing items that are specifically designed and manufactured from the start to work as a system.

Sierra Designs has taken that approach in creating its “Cloud Layering System.” New this year, the layering system offers you three pieces of outerwear to keep you warm, dry, and comfortable on your national park adventures.

The three key parts of the system are a light "windshell," and even lighter "airshell" that is waterproof and breathable, and an ultralight jacket featuring Sierra Designs' proprietary 800-fill hydrophobic DriDown™ insulation that has been treated not only to repel water, but also to dry-out more quickly than untreated down insulation once it's wet.

Part of the beauty of this system is that all three pieces are designed to function as a unit. Combined, they offer a lightweight, packable layering system that weighs less than 2 pounds.

* The Cloud Windshell (MSRP $119), at just 6 ounces, offers breathable protection and a measure of warmth when worn over a baselayer.

* The Cloud Airshell (MSRP ($125), at just 4 ounces, is intended to be worn only when you're getting rained on; otherwise, you stand the chance of getting wet from the inside out.

* The Cloud Puffy (MSRP $249) weighs 12 ounces and will easily keep you warm when the temperature dips into the mid-20° range, possibly lower depending on the baselayers and any mid-layers you're wearing.

As envisioned by Sierra Designs' engineers, this jacket is intended to be pulled out of your pack when you stop for lunch or reach your campsite, although I've used it for short winter hikes.

The Cloud Puffy comes with an attached hood as well as an interior zip pocket handy for carrying your cell phone or MP3 player. The Cloud Windshell also offers one interior chest pocket that also serves as a stuff sack for this jacket. The Airshell also features an attached hood and comes with its own stuff sack.

There also is a rain pants component available to round out this collection of outerwear.

Add these items to your gear list, and you'll be covered for most conditions you'll encounter in the parks.