Producing nature-identical snow

We are able to produce nature-identical snow in our cold-laboratories in Davos.

Why do we need nature-identical snow?

The snow produced in the cold laboratory is used for scientific studies on snow behaviour. In summer it is often too complicated or even impossible to get fresh snow from nature. Also snow collected in nature always varies in density and other properties.
With the “snowmaker” we have the possibility to reproduce always the desired kind of snow what is often a requirement for scientific experiments. The snow differs from the one produced by snowguns which are used in ski-regions. Instead of little ice grains we get real grown crystals.

Further applications

There are still a lot of unanswered questions about the conditions that are necessary for the growth of snow crystals. E.g. one wants to know how chemical substances are being absorbed in snow and how they influence it. This can be an important factor for the lower atmospheric layers.

How it works

The idea is to blow cold air over a heated basin of water to get super saturated air. Afterwards the air will rise up and condensate on a couple of thin nylon threads. Here ice-crystals can grow and will fall down in a box once they are heavy enough (figure 1).

Figure 1 - Scheme

The goal is to repeatable produce different kinds of snow according to the morphology dia-gram (figure 2). So far we are able to produce snow with a density between 30 and 120 Kg/m3 while the maximum output is about 0.3 Kg/h. Mentionable amounts of crystals can produced as dendrites, needles and ice pellets as seen in figures 3-5. The parameters that determine the shape are temperature, which corresponds to the room temperature of the cold lab, and supersaturation, which is indirectly controlled via the water temperature of the water basin.

Figure 2 - Morphology diagramm, Kenneth G. Libbrecht.

Figure 3-5 - Dendrites, needles, ice pellets

The device

The device we use was build after the prototype by Nakamura (1978) and recently modified (figure 6) after several month of testing.
The air is blown by a cross-flow radiator fan with a maximum flow rate of 300 m3/h which is controlled by a frequency inverter.
The water-heating is realized by mineral insulated heating pipeline which is controlled by a resistance thermometer and a digital meter.

Figure 6 - Current design of the device