I hardly ever treat my water that far south
, the occasional iodine tablet... with that being said...
Most of all the cases on the Appalachian Trail were people believe they've gotten Giardia was in fact norovirus..
Sawyer mini, was popular last year... as I said.. it's not really needed..
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Opinions vary on this. The notion that filtration is needed or not needed being opinions, its really up to the individual to decide based on the level of risk/consequence they are willing to tolerate.
I know many who don't filter, their experience has been relatively good in that regard. Mine has been opposite and my tolerance of risk is low when it comes to something so easily preventable. One coin, two sides.
Not quite sure why I am chiming in, as I rarely hike overnight when it gets below freezing. But, I have a question. Wouldn't Aqua Mira freeze as well? Seems like you'd have the same challenge of keeping the little bottles warm as you do with keeping the filter warm.
My experience up here in Southern Canada is that our streams are often below freezing in winter – as long as they're running vigorously. A favourite demonstration of mine teaching outdoors is winter is to pull a clear plastic water bottle out of my pack, dip it into the stream to fill it, and then set it down. Liquid water below freezing crystallizes and freezes starting within seconds when it stops moving. Within a minute or so, the bottle is filled with slush and ice.
Kinetic Molecular Theory, anyone?
22* F from liquid water running out from a glacier placing thermometer in the stream for 15-20 mins. Later the thermometer I used agreed with readings of two other thermometers. The thermometer was not detective and I very well know how to correctly read a thermometer. The temp reading on the thermometer I was using was verified by the two others in my party. It was likely not pure water as said earlier.
Watch this video for something of interest:
I've always used the sawyer squeeze but like others have said above make sure to keep it in a ziplock baggy in your sleeping bag at night, along with electronics. I've had to replace more than a couple times due to freezing.
I can confirm freezing messes them up though. On the AT mine froze and a week or so later I had giardia.
- Young Blood | AT2015 | PCT2016 | CDT2017
FreeGoldRush, did that video help you out any?
We still have a disconnect on this thread between the idea of super-cooled water existing in controlled situation vs. liquid, subfreezing running water.
No duh, super-cooled water exists under certain circumstances. But its existence does not mean that running water in the winter is super-cooled.
Over the three pages of comments in this thread, only one, Trailliam above, presents any first hand experience or even reference to science supporting the idea that water running in winter freezing rapidly after being withdrawn from a stream.
It is likely that vigorously running water in sub-zero conditions is super-cooled, at least somewhat. But how much really? Could you dilute it a little with water from your pack and keep it from freezing? Dogwood suggests glacier water can get into the low 20s F. My experience with glacier runoff is that it flows when things warm up during the day and ceases flowing at night when it is no longer melting. And, I've filled lots of water bottles with glacier runoff, often while on or under glaciers, and I've never had it freeze in my bottle, even though it was very cold.
It is also probable that running water in the 20s - 30s F (conditions representing the most common winter conditions for most of us) is NOT super-cooled and will not freeze after being removed from the stream, and can thus be filtered safely.
It would be really awesome to figure out some guidelines regarding when we might encounter super-cooled water and need to be careful and when it's not an issue. I have certainly never had water from running winter streams freeze in my water bottles immediately after filling them, and that's a few hundred times in temperatures often in the teens (F). Although, I must confess, when it gets cold, I am more often melting snow than finding running water.
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This thread also seems to have a bizarre fear of freezing Sawyer filters. Yeah, they are wrecked if they are frozen, so keep it next to your body and not frozen. This is not a hard task and still a concern even in the spring and fall when temps drop below freezing.
If water freezes in your filter while filtering, it's not going to fail without your knowledge. If somehow you try and filter super-cooled water, it will also plug the filter, so you'll know you have an issue.
I'm not lost. I'm exploring.
No. That video demonstrates conditions very different than what you find in a mountain stream. Water must be stagnant to get the results in that video, and there are many people showing off that fact on YouTube. It must also be free of impurities as much as possible. You won't find any YouTube videos of people doing that with water from a mountain stream because it does not happen.
Oops, wasted my time I did :-)
Well, ANYWAY...thanks to the few that kept their response tied to the original question.
I think I have been sold on AM.