Tuesday, 18 February 2014

Snow architecture

The Winter Olympics were held in Nagano sixteen years ago. With less than a month to go, there wasn't enough snow, and there were worries about events needing to be cancelled. Some of the organising committee went to a local shrine and prayed for snow. The gods answered their prayers and on 15th January it snowed. And snowed and snowed. Although Matsumoto wasn't holding any of the events, it was affected by this divine intervention, with a snowfall of 69 cm, the biggest since records began. This was hailed as one of those once-a-century snow falls, although 1946 seems to have been a bit snowy too. 

Last week it snowed 49 cm. Another one of those once-a-century snowfalls, then on Valentines day and into the next day it snowed 75 cm, so these once-a-century events seem to be getting a bit more frequent. Climatologist James Hansen, formerly of NASA claims that global warming means once-a-millennium weather events will happen once a century, and once-a-century events every decade, and decadal events every year. Read how warm was this summer here.

Anyway, one big impact locally is that there is a metre of snow on the ground. My obvious reaction is one of joy. People pay money to go on holiday for this kind of stuff, and there it is, right outside my window! Everyone else is muttering and grumbling about having to clear it, which is a civic duty here, since there are no municipal snow-clearing facilities. It's the height of shame in the neighbourhood if you're not out there shovelling snow the moment there's more than a few centimetres. 

As well as the mechanical implications of this, and the dangers of injury from shovelling too much or too quickly, I realised the worst thing for your health could be to not enjoy shovelling snow. So rather than digging from the road and the drive into a big pile against the neighbour's wall, and increasingly falling over the neighbour's wall, I decided to roll some of the snow up into giant snowballs and start making an igloo. At the beginning I was making an igloo while  clearing snow, but pretty soon I was clearing snow as a consequence of my igloo building project.

I've tried making igloos before, but never been successful. I've managed to dig a hole into a large pile of snow, but that doesn't really count, and usually doesn't get very big. I've managed to make a ring of big snowballs before and started contemplating the roof, but usually the snow needing clearing has run out, and the problem of making the roof has been too great. 

An igloo is a dome. An arch rotated into three dimensions. As such, it's a very strong structure. The weight of each part is transferred laterally, and I've heard that the bigger arches get, the stronger they get. The problem is that they only have this great strength when they are complete. Until the top-stone is in place, an arch is just two bent walls that are likely to fall over. 

So it was easy enough to make the bottom of the wall, and another layer of snow balls on top of that slightly further in. Then I started to worry. The form was fine but the process perplexing. My respect for those ancient arctic architects grew.

After a while I realised that I could keep building the structure upwards with smaller arches, not going through the middle of the dome, but from adjacent snowballs, then further apart. 

I also got better at making snowballs. In fact they were more like snow-bricks, from forcing my snow-shovel in, and packing the snow onto it. Better still were those cut out of trampled snow with a spade.

A big snowball made the lintel over the doorway, and then it was easy to fill the hole at the top. Next I used the same principle to build an arched entrance, just like they have on real igloos.

So this first igloo has taken me 46 years to build, but the next one should be a bit quicker!

See how the experts do it