Figured I'd post a review of something I will NOT go into the mountains without, but that doesn't seem to be appreciated outside Norway.
The Mountain Tarp (Fjellduken, the Jervenbag, the Wolverinebag) is multi-use tarp/bivvi bag/poncho/ski-sail/tent, that is considered essential survival kit for Norwegian hunters and outdoorsmen, and is also issued to select military personnel.
Jerven's home page is only in Norwegian (pretty sure they used to have an English page, too -- where'd it go?) so I guess I need to do more than just link to their page (
www.jerven.no).
The concept A large waterproof rectangular tarp with zippers on all sides, and two small zippered arm-openings.
Its main uses are as:
- poncho, big enough to also cover a large rucksack
- windsack, when you pull your feet up into the poncho and close the bottom zipper. Favorite of Norwegian reindeer and moose hunters
- sleeping bag cover
- sleeping bag (insulated versions)
- bivouac
- tent (with tent end-pieces attached)
- skiing sail when you're lucky with the direction of the wind
and whatever else you might think of.
Several tarps may be zippered together. They come in four different sizes, weighing from about a pound to three pounds.
The material Thin waterproof synthetic, with a heat-reflective aluminum coating on the inside. It does not really breathe, so some condensation will form on the inside. Not enough to bother me, though; but could be an issue after a few days if it's used as a sleeping bag and not allowed to dry between uses. The outside comes in olive drab, forest camo, mountain camo, or blaze orange.
In addition to the thin lightweight, it comes in two different thicknesses of insulation, plus a new version (MultiMate) with a removable liner. With the thickest tarp, there has been measured a temperature difference between outside (winter storm blowing) and inside of 190 degrees Fahrenheit/ including wind chill factor, and 118 degrees/ discounting wind chill, during testing.
Personal experience I have carried the lightest version (650 grams) with me for several years in the Norwegian mountains, summer as winter, skiing, hiking, and hunting.
I have used it mostly as a poncho/windsack, when stuck on a windy reindeer post. I have my arms outside the bag through the small side zippers, and when it's really cold I pull my feet up and close the bottom zipper.
The mountain camo version looks like lichen-covered stone, and is insanely effective camouflage when sitting still.
As a piece of emergency kit, even the thinnest tarp used as a windsack should keep you alive for a long time -- assuming you have at least a decent woolen sweater under your shell clothing, and that it's not mid-winter. The Norwegian Army teaches you to put a tea candle down an empty food or drink can, and use that for a stove. It is supposed to be surprisingly effective, but I have not tried it myself yet.
I have read a test, where the tester took the Thermo Extreme with him into the autumn mountains (rain,wind, a few degrees above freezing during the day, below at night) for a few days -- no waterproof shell clothing, no sleeping bag or mat, no tent.
And no problem at all -- he reported having been rather comfortable.
On a Norwegian hunting forum, a poll showed that roughly half of the hunters owned and used the "Fjellduken".
Jerven also makes a jacket in mountain camouflage, but it is too warm and doesn't breathe, and so is of little use to me.
They also make a huge modular tent that I have no experience with, but that looks like a decent replacement for a tipi/lavvu. The MultiMate tarps can be used to add "bedrooms" to the main tent.
The prices for the tarps range from $150 to $400, and I think they can be ordered from the manufacturer. If not, and if anyone is interested, I should be able to find someone who will ship abroad for you.
I am not associated with this product, other than as a very satisfied user.