Welcome Innsbruck - Winter 2017/18

W E L C O M E 20 W I N T E R E I N E K U R Z E S C H N E E G E S C H I C H T E Bereits im 17. Jahrhundert, inmitten der „kleinen Eiszeit“, machten sich Gelehrte daran, das Mysterium der Schneeflocke zu erforschen. 1611 entdeckte der Naturphilosoph, Mathematiker und Astronom Johannes Kepler, dass Schneekristalle immer sechseckig sind, und verfasste dazu ein 30-seitiges Büchlein. Es ist die erste schriftliche Abhandlung über die sechszählige Symmetrie des Schnees und über die Einzigartigkeit jeder Schneeflocke. „Plättchen aus Eis. Sehr flach, sehr poliert und sehr transparent, ungefähr von der Dicke eines Blattes Papier. Aber perfekt in Sechsecken geformt. Ihre sechs Seiten waren so gerade und die sechs Winkel so gleich, dass es unmöglich für einen Menschen wäre, etwas so Genaues herzustel- len“, schreibt er darin. Seit 1952 gibt es sieben offizielle Schneeflo- ckenkategorien, festgelegt von der Internationalen Kommission für Schnee und Eis. Was ihre Struktur betrifft, gibt es Wissenschaftlern zufolge 35 Typen von Schneekristallen. Alle Schneekristalle wach- sen aus einem sechseckigen Prisma. Dieses kann eine lange Säule, ein flaches Plättchen oder etwas dazwischen sein. In ihrer Ausprä- gung ist aber jede Schneeflocke einzigartig. A S H O R T S N O W H I S T O R Y As early as the 17th century, in the middle of the Little Ice Age, scholars began to explore the mystery of the snowflake. In 1611, the natural philosopher, mathematician and astronomer Johannes Kepler discovered that snow crystals are always hexagonal und wrote a thirty-page pamphlet on the subject. It is the first written treatise on the hexad symmetry of snow and the uniqueness of every snowflake. „These were little plates of ice, very flat, very pol- ished, very transparent, about the thickness of a sheet of rather thick paper ... but so perfectly formed in hexagons, and of which the six sides were so straight, and the six angles so equal, that it is impossible for men to make anything so exact,“ it says there. Since 1952, there have been seven official snowflake catego- ries, defined by the International Commission on Snow and Ice. As far as their structure goes, scientists have come up with thirty-five types of snow crystals. All snow crystals grow from a six-cornered prisma. This can be a long column, a flat little plate, or something in between. In its final appearance, though, every snowflake is per- fectly unique.. old. Maybe winter, as we know it today, will be forgotten some day. But we are still a long way from that. The winter is not only beautiful, it is also vital for extensive areas and its inhabitants. If it doesn’t do what it is supposed to do, we simply give it a leg up. G R O W I N G T O G E T H E R “At Schneezentrum Tirol we follow two major directions,” Rothleitner ex- plains. One of them is snow management: when do you make technical snow and in which quantities? “At the end of the season, a lot of technical snow usually is left on the slopes, which was produced also because of the worry that not enough snow would fall from the sky. Here we want to develop management methods in order to make savings.” The second area is the technology and deals with the question of how to produce snow more efficiently, i.e. more economically and more ecologically. If we want to be precise, technically produced snow – or artificial snow, as it is usually called – is not really snow at all. It rather consists of ice particles, which have little in common with the artful ice crystals apart from their aggregate state. Where technical snow has the advantage over its natural brother is in its longevity. “Which is due to the water content,” Rothleitner points out. Natural snow comes with a weight of thirty to three hundred kilograms per cubic metre. The lower the weight, the less water, the more powdery the snow. Technical snow weighs around four hundred and fifty kilograms per cubic metre. That’s why it’s so easy to work with, because it’s much more compact than natural snow. “Powdery fresh snow cannot be worked on with snow groomers, as the individual crystals do not interconnect.” Snow becomes powdery when humidity is very low. And it has a veritable binding aversion. What is needed for a good sintering – that’s what the growing together of individual snowflakes is called – is smaller, round grains. The numerous contact points allow the grains to grow together in various places. In this way the snow ac- quires greater firmness – perfect for the slope. D E T A I L S The technology of artificial snow production is not new, yet still there are many open questions. The one, for example, as to how much snow actually Mittlerweile gibt es drei Prototypen einer entsprechenden Messsonde, die Schneefeuchte messen soll – zwei davon wurden in Innsbruck entwickelt. Diese Messgeräte werden nun in der Praxis getestet. // There are three measuring probe prototypes to be used for measuring snow humidity, two of which have been developed in Innsbruck. These devices are now tested in the field. © SCHNEEZENTRUM TIROL