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rachelsdad 02-18-2017 08:48 AM

Condensation ?
Been backpacking over 35 years but I'm looking for some advice on a real basic issue

Not sure if I brought this up before but last summer on my last leg of the NPT I took a new Big Agnes Scout. Never used it before but I was doing 16 miles that day and I needed to pare weight.

I'm doing the CL 50 this spring...(anyone wanna come along)..and I'd like to bring that w/me but I had a serious condensation issue with it that night...drenched inside and out...and I did not even sleep in it.

It was pitched in the open, clear night, flap open. Ended up sleeping in the lean-to. Didn't think it was all that humid but anything left outside of the lean-to was drenched. I'm leery of hauling a single wall tent after that, but I have to believe no tent would have escaped unscathed.

A friend had his Half Dome tent under canopy, no issues. So I suppose that is the answer but I figured I'd ask here.

So....What happened? And how can I avoid it?

Trail Boss 02-18-2017 10:39 AM

Humidity produced by you (perspiration, breathing, etc) condensed on the first cool surface it encountered, namely the polyurethane-coated rain-fly.

The same thing happens in a double-wall tent. The humidity condenses on the cool rain-fly ... except the inner tent-canopy helps prevent the water from dripping back down on you or getting you soaked when you brush against the interior of the tent.

In winter, the moisture can condense on the inner tent-canopy and then, if disturbed, create an indoor snowfall.

Ventilation helps but, to work, it's best if the outside air is less humid than the air within the tent.

An "open clear night" can present an added challenge. Dew is created when the earth's surface cools faster than the air's moisture can evaporate. The moisture condenses on the rapidly cooling surface, namely everything at ground level. In other words, on a nice clear night, ambient humidity can increase substantially and make it difficult to keep anything dry even if it is under cover.

rachelsdad 02-19-2017 03:19 AM

Humidity produced by you (perspiration, breathing, etc) condensed on the first cool surface it encountered, namely the polyurethane-coated rain-fly

I was sleeping in the lean to...

I know it seems like a dumb question but I have never seen a tent so completely saturated.

Trail Boss 02-19-2017 11:07 AM

That was "you" as in the "everyman you". The explanation described the common cause of condensation in a tent.

In your specific case, the final paragraph explains the culprit, namely ideal conditions for the formation of dew. Rapid cooling causes humidity in the air to rise faster than it can evaporate so it condenses on all ground level surfaces.

But if you don't care for that explanation, I can invent "alternative facts" and claim the tent was made of a unique hydrophilic material that attracted all air-borne water molecules in a 50-foot radius thereby rendering it dripping wet. ;)

dundee 02-20-2017 09:17 PM

It was Elvis.

tenderfoot 03-10-2017 09:47 AM

"anyone wanna come along"

Hmmm - when are you thinking?

rachelsdad 03-26-2017 10:35 AM

I'm open to anytime. Only bad weekend is the weekend after the 4th of July...big festival in Star Lake that weekend!!

I would love to do it starting on a Thursday but I can hump some extra miles if a Friday start is needed. I'm in the area so an early Friday start is not out of the question.

tenderfoot 03-28-2017 08:27 PM

I would be flexible with start. Thu afternoon would work. I am in Rochester so would take of Thu and Fri or half of Thu. You said Spring - I'm not right there so am unsure when the window between no snow shoes required and black flies is. I also hear the Cl is very wet so that might factor in.

I am a slow hiker...


rachelsdad 03-29-2017 05:03 AM

I bring a calendar, not a stop watch, so our pace would probably mesh well.

I guess the spring timing was optimistic. I'm not too worried about the snow as much as the , before the big snow dump a few weeks ago.

I'm flexible as well...with enough notice I'm good anytime!

tenderfoot 04-10-2017 12:03 PM

I will PM you once I get back from this week's trip, see if we can match up schedules.

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