UKH

I'm a teacher and so my main winter climbing activity is in the February half term. Over the last couple of years I've been wondering whether it was worth booking a trip up. Last year I had a trip organised but then conditions were so awful so I didn't bother going, thankfully I managed to arrange to do something else at short notice. The year before conditions were generally much better however that week there was a huge dump of snow followed by a rise in temperature and I only got a few routes in. This year I didn't bother at all and have arranged to do something else in advance but it did get me thinking how many good days of winter climbing could you expect to get on average in the secondish(ish) week in February.    

With that in mind I did some very rudimentary research. I plotted out the rough dates of half-term weeks (nine days total from Saturday to the Sunday). I then chose three routes Invernookie, Green Gully and Twisting Gully, which I thought gave me a good spread of areas, were popular enough too give plenty of data but were routes less likely to be climbed in poor conditions (as opposed to ridge routes like Dorsal Arete). I also wasn't interested in harder routes. I recorded whether there had been any climbing on any of these routes for the dates selected just as a y (yes). I also added the data from my logbook, although this only amounted to one extra day. The average number of 'climbable' days came out as 5 and showed a sharp decline from 2009 to 2019, although this will be skewed by the excellent winters of 09/10 and the rubbish one last year.  Obviously this is very rough work. Many people do not log routes on UKC and just because no routes were logged doesn't mean that conditions weren't ok, on the other hand some logs may have been done in poor conditions. Despite all the limitations I hope it might be of some interest. I feel like five days is a reasonable number however these days often come in blocks meaning you have to be fit to make the most of them, this number may also be on the decline although probably not as steeply as shown on my graph.  

https://docs.google.com/spreadsheets/d/e/2PACX-1vSa59C38mKSdstMgoecesjmh1D2...           

That's interesting. To be honest I'm surprised there were so many logs in 2014 and 2017, these being usually regarded as poor winters (2014 due to being generally very stormy, 2017 for general lack of any freeze thaw, much like this/last season). 

A linear model fitted gives the probability of a significant drop over years as p =0.03

The other useful Excel function for testing the probability of Scottish weather would be

=randbetween(0,1)

Your straight line fit looks depressing, but I can't help feeling that a downward tending curve would be a better fit!

Interesting idea. But I feel there are flaws, some of which you acknowledged already.

If 2019 had been up at 7 good days, I think the entire data set would show pretty close to a horizontal line as the best fit, so no real correlation. So your trend might be resting on a single data point.

The tiny number of routes sampled does leave this very open to huge error bars.

You have acknowledged this, but to restate it succinctly: Assuming that recorded sends on UKC is directly correlated to quality of conditions is not something you can really do without some evidence for it.

I think looking at historical weather data from places like Cairgorm Summit station and others would be a more accurate way to track numbers of days with good conditions (you could set temperature, precipitation and wind speed definitions of what would be a "good day").

It is fairly simple..  usually the week before but sometimes the week after you plan to go...

As an alternative your could consider what a number of my teaching friends do. Book early cheap flights to Marseille. If the ice conditions are good, it's a couple of hours drive to the north. If bad, there's lots of sunny climbing venues surrounding Marseille. Cheap accommodation can be booked last minute.

The other thing is that 2018 was one of the best winters of recent years, with almost continuous good conditions, so it seems like the OP has chosen (by chance) one of the rare poorer weeks for that year. 

Great piece of work and well understood comments about the limitations of such tables. This season has been a funny one. In contrast to last year there seems to have been plenty of snow but rapid thaw over the following days leaving slush. It seems to be either deep powder or soggy wet rubbish. I frustrating season so far. We're going up in around 2 weeks and hoping for something.

I think the season has been very similar to last year - repeated thaws and back to square one every time you get a brief colder spell. Which season you consider 'better' probably depends on which days you're able to get out. I agree it's been frustrating!

As someone responsible for a few of the Green Gully and Twisting Gully ticks, I can confirm this is a serious flaw in the methodology! 

Indeed, that was a particularly frustrating week, especially as friends up the week after got great conditions. Doing it for the whole of the month would have given a better data set but I couldn’t be bothered. 

as in conditions were rubbish? Presumably they were climbable?

Conditions were masochistic

What is masochistic conditions? Deep powder?

Wouldn't counting the number of ticks for those routes, rather than just a binary y/n, give you a much better data set? Admittedly this wouldn't translate so well to determining a "probability" for the possibility of climbing on any given day, but that's a pretty loosely defined concept. If you do this you might also want to scale the weekend data to account for the increased availability of climbers, or perhaps just exclude them?

Since half term will shift from year to year, why not just take use a fixed set of dates in the middle of February? Again, you'll need to make sure you're accounting for the same number of weekend/midweek days.

Finally, you're making an implicit assumption that the number and geographical distribution of winter climbers who log routes on UKC hasn't changed over this period. I'd hazard a guess that it probably has, although I can't be bothered to try and find any stats on this. Have you looked into this?

I would hypothesise that the number of winter climbers logging routes on UKC goes up and down depending on whether the route is in nick or not.

Wind so strong as to peel your eyelids back. Air so cold as to freeze your nostrils up. Patinas of ice that shatter, sending you down with a clatter. Spindrift whirling inside your hood, going down your back, filling your ear canals. Snowdrifts so deep as to chill your balls. An angry man shouting at you get a move on. An angry mountain, shouting you back down. Cornices the size of coaches. Your soul tied off to gear made of hopes and dreams. 

And yet, it still beats even the comfiest of armchairs and strongest of whiskies.

It complements them - those things seem even better afterwards.