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 Post subject: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 10:13 pm 
The New Guy

Joined: Sun Dec 01, 2013 9:01 pm
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Location: Colorado
Hi

I live in an off grid cabin and am snowed in. Carrying water is very difficult...but snow is everywhere.

Does anyone have experience with melting snow for drinking water...and living like that day in day out? I've read about it a bit but have found almost now information online and also searched this site.

Thanks!


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 10:26 pm 
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That is SOP for norwegian mil on exercise.

Not an issue at all.

Just make sure that you have clean hands or tools when gathering snow, and use a clean container as well as keeping it separate from "dirty" items like fuel or garbage.

For efficiency, don't empty the pot completely on the first go; let some hot water remain in the pot and add snow. Also, use a lid to speed up the process as well ad reducing the amount of vapor inside you shelter.


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 10:35 pm 
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Is there really no water source you can get? Melting snow works, but isn't really energy efficient. If you can melt snow passively as you heat your cabin as usual, it's not as bad but still long.

3 things:
- To drink it, you still need to treat/boil melted snow to kill bacteria
- Chemical water treatments need a lot more time to work in cold water (varies depending on the solution)
- Depending on snow density, you're likely to need 5 times the volume of snow (often a lot more than that) to the volume of water you want.

Easiest way is to have a very large pot you can keep on top of your stove (assuming you have one) and add snow every now and then as it melts. The more water there is, the faster snow will melt. But that requires you to maintain it and add snow frequently to get any sizeable amount of water.

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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 10:49 pm 
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How can you say it isn't energy efficient?

I have done it for a long time, using snow as the primary source of water in the field.

It is no issue at all.

And I do not think he was referring to not using a heat source. Besides, you only need to heat it up to 72 degrees C to kill off the bad bacteria. Not that snow is very unclean to begin with.


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 10:50 pm 
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Get a huge pot. We have an old iron pot which is somewhere between 30 and 40 liters, which sits on the kerosene stove all day. It never boils the water, and we've never had any problems with it. Use clean snow and clean tools and you're good to go.

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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 10:53 pm 
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Conker is right. Combining the melting process with space heating is the best way to go about it.
Melting snow is a continuous process - you don't just melt that 1L you need right then, but just keep it going as long as you have containers to maintain the melted water in (thermos flasks is a good example).

AGR416 makes a very important point. If your water gets polluted by stuff like fuel, you'll just end up shitting and puking all over the place. Make sure you keep your water and anything that comes into contact with it (equipment, pots, flasks, bottles) clear of pollutants.

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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:01 pm 
The New Guy

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Location: Colorado
Thank you! I have a woodstove and propane stove. The woodstove would be perfect since I already use it for heat and then reserve the propane stove for cooking. I just need to get a large pot.

And great to know about 72celsius is all I need to kill bacteria. I thought I needed to boil it which meant transfering water from the woodstove to the propane...and that starts becoming a hassle and drain on propane...even with a pressure cooker.


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:05 pm 
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AGR416 wrote:
How can you say it isn't energy efficient?

[...]

And I do not think he was referring to not using a heat source. Besides, you only need to heat it up to 72 degrees C to kill off the bad bacteria. Not that snow is very unclean to begin with.


It isn't if you need to melt snow in an open area, say when stopping for a meal or when you're in an half-shelter. Combining it with heating space (ie a cabin) isn't too bad.

Indeed snow isn't as bad as most water sources, but it's still good precaution to boil it. There are algae, bacteria and other pollutants (depending on the area). If there's piss/crap in the snow but it has snowed on top of it, you won't see it... Sometimes these contaminants are visible, sometimes not. While not *necessary* all the time, once water is warm it's not much harder to boil it...
http://www.summitpost.org/exploring-the ... now/640549

You may dig a bit more but as quick overview this does the job: http://www.backpacker.com/community/ask_buck/412

As for how long/how hot should it boil:
Quote:
If the water is cloudy, filter it through clean cloths or allow it to settle, and draw off the clear water for boiling. Boil the water for one minute, let it cool, and store it in clean containers with covers.

Source: http://water.epa.gov/drink/emerprep/eme ... cfm#method

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Last edited by Conker on Sun Dec 01, 2013 11:12 pm, edited 1 time in total.

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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:09 pm 
The New Guy

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Location: Colorado
thanks for the link. my only neighbors are wildlife so the pollutant is either from animals, maybe soot from the wood stove or air pollution in the snow. soot and animal waste i can see. air pollutants...well...not sure if its any worse than ground water although here in colorado there has been acid rain


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:14 pm 
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Quote:
It isn't if you need to melt snow in an open area, say when stopping for a meal or when you're in an half-shelter.


Bullshit.

I assume you really haven't done this much, have you?

I have melted snow as the primary water source for 11 years in the military, not just for food, but for drinking water as well. Back in the day we did not have a Thermos or the like, just our canteens.

Is it as quick as just boiling water? No, of course not. It is, however, way better than humping enormous amounts of water.

Quote:
Indeed snow isn't as bad as most water sources, but it's still good precaution to boil it. You may dig a bit more but as quick overview this does the job:


Is that the same source as the previous one, that did the article on fishnet base layers? If so, they are really clueless. What he is stating is pretty effin' obvious. Avoid tainted areas? Really Sherlock?

Again, a tip to add some water to your canteen after drinking is to add snow and let it melt. You can also make a little ball of snow and stuff it in your mouth and let it melt, for drinking water as you are moving.

Quote:
And great to know about 72celsius is all I need to kill bacteria.


You can thank Louis Pasteur.


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:21 pm 
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AGR416 wrote:
Is it as quick as just boiling water? No, of course not. It is, however, way better than humping enormous amounts of water.

That^^ was my point. If water is accessible by digging a bit to have access to a stream however small it is, it's worth it.

All I'm saying is that it takes quite some time and effort. If you're away from "liquid water" for a day and can carry enough that time, it's, in my opinion, much less trouble. Obviously for several days this doesn't work. I'm not even contradicting you, I agree with you. In the OP's situation - in a cabin, it's not much of an issue as (I assume) he'll be heating the cabin anyway.

AGR416 wrote:
What he is stating is pretty effin' obvious. Avoid tainted areas? Really Sherlock?

It's not always in concentrations that make it visible, and as with any other contaminant it can be easily covered by blowing snow or precipitations.

The article is actually well-researched and has external links for more scientific details from what are pretty reliable sources. The article itself is an easy to read summary. I know that I, for one, would tl;dr the original sources which is why I linked to the article. If you want to call bullshit you might want to take the time to read them.

AGR416 wrote:
And great to know about 72celsius is all I need to kill bacteria.
You can thank Louis Pasteur.

As for that, I'll be honest I don't have personal knowldge to make a call. I'd tend to follow the EPA's guidelines... but what do they know?

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Last edited by Conker on Sun Dec 01, 2013 11:39 pm, edited 2 times in total.

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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:35 pm 
The New Guy

Joined: Sun Dec 01, 2013 9:01 pm
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Location: Colorado
If 72 celsius kills all bacteria, why do i need to boil it?

I'm hesitant to put too much stock in the EPA. Americans are really paranoid about cleanliness...for example, they obsess about refrigerating cheese. Years ago a French marketing expert was hired by an American cheese company to give them advice. He told them in France cheese is consider alive and putting it in the fridge is like putting a living chicken in the fridge. But in America its about being sterile. He suggested selling cheese in resealable zip lock bags . Dont know about Europe but that is very popular here in the states.


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:43 pm 
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Making water potable:
Quote:
As a method of disinfecting water, bringing it to its boiling point at 100 °C (212 °F), is the oldest and most effective way since it does not affect the taste, is effective despite contaminants or particles present in it, and is a single step process which eliminates most microbes causing intestine related diseases.[3] In places having a proper water purification system, it is only advocated as an emergency treatment method or for obtaining potable water in the wilderness or in rural areas,[4] but it cannot remove chemical toxins or impurities.[5]

The elimination of micro-organisms by boiling follows first-order kinetics—at high temperatures it is achieved in less time and at lower, in more time. The heat sensitivity of micro-organisms varies, at 70 °C (158 °F), Giardia species (causes Giardiasis) can take ten minutes for complete inactivation, most intestine affecting microbes and E. coli (gastroenteritis) take less than a minute; at boiling point, Vibrio cholerae (cholera) takes ten seconds and hepatitis A virus (causes the symptom of jaundice), one minute. Boiling does not ensure the elimination of all micro-organisms, the bacterial spores Clostridium can survive at 100 °C (212 °F) but are not water-borne or intestine affecting. Thus for human health, complete sterilization of water is not required.[3]

The traditional advice of boiling water for ten minutes is mainly for additional safety, since microbes start getting eliminated at temperatures greater than 60 °C (140 °F) and bringing it to its boiling point is also a useful indication that can be seen without the help of a thermometer, and by this time, the water is disinfected. Though the boiling point decreases with increasing altitude, it is not enough to affect the disinfecting process.[3][6]

Sources:
  1. Taylor, R.A., Phelan, P.E., Pool boiling of nanofluids: Comprehensive review of existing data and limited new data, International Journal of Heat and Mass Transfer, Volume 52, Issues 23–24, November 2009, Pages 5339–5347
  2. Robert A Taylor, Patrick E Phelan, Todd Otanicar, Ronald J Adrian, Ravi S Prasher, Vapor generation in a nanoparticle liquid suspension using a focused, continuous laser, Applied Physics Letters, Volume:95 , Issue: 16, 2009
  3. Howard Backer (2002). "Water Disinfection for International and Wilderness Travelers". Oxford journals. pp. 355–364. doi:10.1086/324747. Retrieved 20 July 2013.
  4. "Emergency Disinfection of Drinking Water". EPA. Retrieved 20 July 2013.
  5. OA Guide to Water Purification, The Backpacker's Field Manual, by Rick Curtis, first edition published by Random House March, 1998
  6. "Is it true that you can't make a decent cup of tea up a mountain?". physics.org. Retrieved 2 November 2012.
  7. IAPWS. "What is the effect of pressure on the boiling of water? Why does water boil at a lower temperature at high altitudes?". FAQs About Water and Steam. Retrieved 2009-12-05.

Could you get away with 72? Sure. You probably won't have any issue even if you don't get it to 72 assuming you're in a remote area. Hell, in India some people drink from the Gange. Is the minimal effort to boil it 1 min worth it? I personally don't want to take chances and get diarrhea when I'm in a remote area, so I would. But AGR is right, it's probably not necessary.

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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:48 pm 
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Quote:
If 72 celsius kills all bacteria, why do i need to boil it?


Like I said, not all bacteria, but bad bacteria.

Quote:
As for that, I'll be honest I don't have personal knowldge to make a call. I'd tend to follow the EPA's guidelines... but what do they know?


Do you know who Louis Pasteur is? Pasteurization?

http://en.wikipedia.org/wiki/Pasteurization

Humans do not need sterile food.

If the snow in your area is contaminated by e.coli, you should probably boil it, but I don't think it is very likely.


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 Post subject: Re: Melting snow for drinking water
PostPosted: Sun Dec 01, 2013 11:52 pm 
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@Conker:

That relates to actual water, not melting snow.

I have had E.coli in the drinking water where I lived at my last duty station. We boiled it, and were fine.

As long as the snow is white and clean, you will be ok.


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