Fall is coming and the big question for many campers is whether to pack a regular three-season tent or go all out an splurge on a four-season. I asked Eureka Canada’s expert, Jim Stevens, to explain in all in detail in my second edition of The Complete Guide to Winter Camping (to be released mid-September). Here’s what he had to say.
Jim Stevens from Eureka Canada (now retired, and eager to pitch his tent more this coming fall):
I often get asked questions about the differences between three- and four-season tents. What are the differences that qualifies a tent to be four-season? Why is there such a weight difference? Must I use a four-season tent for fall and winter camping? All valid questions.
We should probably begin by understanding labels and targeted applications. A four-season tent, although there is no universal standard, will have common features when built by any reputable tent manufacturer. Any tent designated as four-season has been tested, both in controlled facilities and on expeditions, to meet requirements found at high elevations (alpine) and above tree lines (Arctic). These tents must be able to withstand snow loads and extreme winds. This does not preclude them from being used year-round; in fact, they make excellent shelters in warmer weather.
A three-season tent focuses on weather protection but not to the extreme levels of a four season. Many three-season tents can be used for winter use, but users must know the terrain and typical conditions they will encounter. If hit by a heavy snowfall you would expect to have to clear it off to avoid the risk of the tent collapsing. Similarly, extreme winds may require a move to a better protected site.
Frames. All four-season tents will use aircraft aluminum frames and in a design that maximizes strength to handle snow load and high winds. To achieve this needed strength, most four-season tents will use four poles or more. Three-season tents almost always use aluminum (fibreglass can be a lower cost option) but in designs that focus on lighter weights. Poles are often reduced to two and, in some designs, non-freestanding.
Floors. Most four-season tents will use heavier fabric floors with higher polyurethane (PU) coating levels for greater waterproofness. Most often used floor fabrics will be a 70 Denier (D) nylon, 75D polyester or 150D polyester. The PU coating levels will start around 3000mm (indicates fabric can withstand water pressure equal to three meters) with some higher. These coatings are typically higher than many three season tents as four-season tents are often pitched on snow. The potential for the snow to melt exists this the higher coatings. Three season tents can use floor coatings starting around 1200mm. If you are an avid camper having the chance to be outdoors over 25 nights a season, then you will probably focus on a tent with higher floor coatings.
Inner Walls. The walls of a four-season tent will use a breathable fabric with some mesh panels. Most panels use zippers to close. Breathable fabrics are better at holding in warmth or, conversely, keeping out cold. Three season tents often use all mesh or mostly mesh walls. This is done to lower weight, lower cost and can have the advantage of being cooler in warmer weather. Just be aware that if being used in freezing temperatures you will require a warmer sleeping bag, clothing, than if you were in a four-season tent in these same conditions.
Fly Sheets. All three- and four-season tents will use full coverage fly sheets for full weather protection. Fabrics used on for season tents will most often use heavier materials as these have been proven over years of use as the most durable. Polyester fabrics of 68D or 75D, usually ripstop, are used with PU coatings no lower than 1500mm. Three season tents, in efforts to reduce weight, have been using fabrics as thin as 20D (recently, even thinner). Some lighter fabrics are starting to be used on four season fly sheets but knowing the extreme conditions these tents must meet it will be a careful process. One other major difference on a four season fly sheet is the size of the vestibule (door covered porch). Four season tents have larger vestibules with one of the primary uses being a cooking area. This is a contentious issue as it is always recommended that use of any open flame (stoves) be a safe distance from the tents. Tents sold in Canada must meet Canadian fire-retardant standards, meaning they self-extinguish when accidentally contacting a fire source, but the fabrics will melt if in contact with an open flame. Experienced winter campers, alpinists, will experience situations where they must use stoves in a vestibule but will take every precaution to avoid any mishap.