[Will Hunt]

Lantern season is soon to be upon us. In my experience it can be a very hit or miss activity. Sometimes great connies, other times the conditions are worse than summer due to huge amounts of condensation/rising dew/whatever it is - basically holds getting filthily wet at the slightest touch of the hand.

Following on from Pete's excellent Diamond conditions thread, is there any SCIENCE we can employ here? For the Diamond, it seems like you would need a gap of 8 or more degrees between air and dew point temperatures and probably a bit of wind besides. This never seems to happen in the evenings on the grit though - air temperature drops to close to dew point every night it would seem. Is it just the wind and general air temperature that needs to be factored in?

[tomtom]

I've noticed that conditions tend to be worse when it's raining....

[andy_e]

Except at Earl Crag.

[lagerstarfish]

it gets dark after the sun goes down

[SA Chris]

They say it changes as the sun goes down, round here.

[lagerstarfish]

you're in Shalesmoor?

[SA Chris]

Hunter's Bar

[r-man]

Not from San Francisco?

[andy_e]

Total and utter thread derailment.

[SA Chris]

Sorry. I just look at the humidity forecast on met office. Probably low level accuracy, but at least gives you something to pin the blame on.

[petejh]

All hypothetical but I'd have thought each venue will have slightly unique benchmarks for good connies.

Assuming that there can only be a finite number of variables which affect climbing connies.

Variables I came up with when thinking about the Diamond:
Air temp
Dewpoint temp
Relative humidity (less accurate than dewpopint but more concise)
Wind strength
Wind direction
Pre-exisitng moisure (sea spray or rain) prior to your arrival

For enclosed venues such as Pariselllas I'd add on the warmth from lanterns and people (and turds ) possibly contributing to drying-out condensation.


Then it's *just* a matter of going in various combos of the above variables, knowning in advance the state of each, and noting conditions. Not at all nerdy.

Barrows should research this shit not some unimportant bollocks.

[Will Hunt]

You twats 

If there is no pre existing knowledge then I will just try and collect some data on it this season. My concern is that with a broad number of variables it might be difficult to actually discern which are the dominant factors.

[SA Chris]

All hypothetical but I'd have thought each venue will have slightly unique benchmarks for good connies.

Yes, round here it's "it'll be shite". We get a lot of greasiness, rock getting morning sun, then afternoon shade seems to cause a load of condensation as rock cools, plus a high tide after midday means rock stays damp. Needs a really fresh breeze and low humidity to get anything decent.

[lagerstarfish]

my experience is that at this time of year the grit doesn't suffer condensation in the first part of the evening/night - it's usually more of a morning thing

I guess the rock temp drops slower than the air temp?

[andy_e]

Quite the opposite, air is a very good insulator. Air is heated by the earth's surface warming up. Once the sun goes down, the rock temperature drops rapidly, and the air temperature drops more slowly, leading to a large temperature contrast and condensation.

[Will Hunt]

So in that case you would need to go out some time after dark, or else wait until its properly cold anyway...?

[dave]

Anecdotally, from my experience condensation/dew on grit is rarely a problem unless you're out proper late.

[andy_e]

Hmmm, I'm not sure now, thinking about it. The air would reach dew point much more slowly than the rock would, so perhaps the earlier the better. As the rock is already cooler than the air, it provides a good surface for condensation so once it starts it's probably not very likely to stop.

[Will Hunt]

But conversely to what Dave said, anecdotally I've been up on a high moorland crag over summer and, before the sun has completely gone down, noticed a very sharp deterioration in conditions as condensation starts to form. It wasn't especially hot or cold and it hadn't even got fully dark yet, just entering twilight really

I'm not convinced it will be as location dependent as Pete suggests as we're dealing with crags with largely common factors when we talk about grit. Generally exposed, quick drying edges - no tides or anything to worry about. It would be good to collectively crack this as it does seem fairly random.

[dave]

But conversely to what Dave said, anecdotally I've been up on a high moorland crag over summer and, before the sun has completely gone down, noticed a very sharp deterioration in conditions as condensation starts to form. It wasn't especially hot or cold and it hadn't even got fully dark yet, just entering twilight really

This tends to happen on peak lime quite a bit, at the bottom of steep crags, the Tor being the obvious example.

[bigtuboflard]

Lantern session by someone on Voyager as I ran down Burbage earlier this evening. Would have thought conditions tonight would have been poor as not much of a breeze and a could of heavy showers too passing through.

[andy_e]

This could be useful for predicting dew point from humidity/temperature forecasts from the Met Office:

[Johnny Brown]

A quick glance at the tephigram usually tells me all I need to know, though I'm not much of a night climber.

[andy_e]

Wow. I do like a good confusing graph!

[Drew]

From personal experience I found that if I spent a couple of hours climbing after dark, there would be several dew-pauses as I termed them. Basically the rock seemed to suddenly get a lot more greasy and I couldn't hold what I had held easily 2 minutes before. I realised that leaving it for 10 minutes and having a cup of bovril often gave it time to dissipate, and the condition would improve for another half an hour to an hour.

It wasn't just that I got cold/tired/sweaty as I was often climbing with several other people and they all experienced the extra greasiness at the same time. At first I was the only one to pause and rest/warm back up, thus not trashing my skin, but after a while a few other people would rest, and we all reckoned it improved after 10 minutes or so.

Next time you're out, experiment by having a break and see whether it's better/worse than before. I'd be interested if it's localised to Peak grit or not.