Northface is wellknown for the quality of its products. For a long distance hike in the Austrian Alpes I purchased four copies of the Northface Assault Bivvy, a bivvy bag with DryWall technology; waterproof and extremely breathable.
A bivvy bag is a shell for your sleepingbag, usually it has some extra space for your hiking gear, which protects you from the elements during the night. Some bivvy bags are just simple bags that you slide into with your sleeping bag, but this Assault Bivvy has a head which you can zip up to be completely protected. During long hikes it’s wise to bring a bivvy bag, just in case you’re forced to spend the night on the mountain.
The first night we spent the night at an altitude of 2000m (6562 feet). It was a clear night without any rain and a minimum temperature of 16 degrees celcius (60.8 degrees Fahrenheit).
The next morning we woke up with soaked bivvy bags. And not only the bivvybags were soaked, but our sleepingbags were quite wet too.
Respiration moisture? That even occurs in a regular tent usually.
We slept with a tarp over our heads, and straight below the tarp the bivvy bags were dry. Even while we had them closed and had been breathing in them all night. But the part of the bivvy bag that was not under the tarp was soaked. This must have been the result of the morning dew.
Our conclusion was that we had to end our hike early, with bivvy bags that got soaked even with light morning dew there was no way we could spend the night safely in alpine terrain. The chance of getting soaked resulting in hypothermia were just to big.
Unfortunately later that day we got caught in heavy weather at 2500m (8202 feet) altitude. We were forced to take out the bivvy bags again, with mats and sleepingbags to stay warm, to wait it out and hurry down as soon as the worst was over.
Lightning, heavy hail and rain scourged our bivvy bags for half an hour. In the small space around our heads we could feel the raindrops splash right through the fabric. Within three minutes there was a pool of water in my bivvy bag, within five minutes I was completely soaked, sleepingbag and all.
Luckily we could pack up not much later and get down safely. (read the whole story here in Dutch).
The Specs by Northface
A bivvy bag is supposed to protect you in case of emergency or when used as a lightweight tent.
De Northface Assault Bivvy is lightweight, for sure, but as a bivvy bag it’s rubbish. It is not waterproof, even with light morning dew it does not keep out moisture. The chance of getting soaked resulting in hypothermia is high, using this bivvy in high altitudes areas like the Alpes can be very dangerous.
Do not buy the Northface Assault Bivvy. Even a simple garbage bag will protect you better than this thing.