Mechanical handling of snow

mechanical handling is a PREPARATION for the natural snow

solidification process

diminution of mean grain size

obtaining of different grain sizes

grains become rounder

increase of snow density

man

combination of man and nature

snow

hard

en

ing

Mechanical handling of snow

natural snow solidification

natu

re settlement and sintering

The preparation time depends on:

type of snow (temperature, liquid water content, grain shape) weather forecasts (air temperature, air humidity, net radiation)

The preparation time must be chosen so that the snow hardening is the highest

When does the snow have to be prepared?

dry snow

snow hardening by sintering needs time (settling time is crucial before using the piste)

wet snow

with a high liquid water content, the mechanical handling produces a water layer at the snow surface, which can freeze afterwards the best preparation time is just before the freezing starts

When does the snow have to be prepared?

Influence of settling time on the sintering process

2 hours settling 10 hours settling

Ski Racing is dependent of natural environment. The success of the event is linked on the ‘’HOW’’ we react to a situation. Safety is an important aspect to respect.

Here is an example of ‘’HOW’’ you can save time and energy, also increasing the chance of doing a successful event.

Depending on the race level you are participating, there are various possible implications of sponsors and/or resort staff. A World cup, NorAm and Championship, will come with high involvement of the resort operation team to provide the best event quality, but most of us are doing provincial events which rely on the local ski club and/or provincial organisation. This means possible implication of the resort is not guaranteed and resort involvement in the race should be announced long enough before the race.

It is also important to respect resort rules which are different from one place to the other.

Mechanical handling of snow

Course is set the day before (turning pole only) and forecast for the night is 8-10 inches of snow. Obviously you will have to clean the course in the morning but you already know that you are limited on working crew. At 6h00am, at least 10 inches of new snow cover the whole trail. Snow accumulation is over and every body want to race!

There is a lot of advantage to use machinery early in the morning and prior inspection.

Easier to clean and slip the course Reduce the risk to have a huge snow bump on the course spill zone Prepare the trail for the second run You will be a hero with your idea and the volunteers are going to be grateful.

Example case

First you have made a plan with the ROC, Jury and resort management.

You have to clearly explain to the chief of course, the resort manager or directly to the driver what you want to do and the expected result.

The jury have to delegate a responsible that will be in charge of respecting the plan and coordinating the work. Depending of the level of knowledge involve in the group, you may have to be on site for coordination.

Planning

The grooming machine should come in the trail from the middle and must choose one side (right or left) of the turning gates. Then, angle the blade at 45 and push the snow to the outside of the course. Tiller down and active (no back tilling). The driver must follow the course as close as 2 to 3 meters from the turning pole. The first pass is very important and must be done slowly from top to bottom. The driver must be careful to not breaking the hard surface underneath the soft snow. When reaching finish, come back up on the side close to the fencing with the blade at 45 and tiller active.

The second pass down must be done immediately on the other side of the course with the same pattern as the first pass. This way you will leave more settling time to the snow.

Third pass is down the hill again and in between the gate (Giant and Speeds event). In slalom case middle pass may not be required.

How to proceed

Then, the balance of the job is to flatten the snow on the rest of the trail in preparation for the second run.

If there is a surplus of snow close to the fencing system, you must push it on the other side at atlease 4 meters from the B-fence. Finally, volunteers are coming on the course to start removing the fresh snow on the race line. The good news is they remove the snow from the race line, over a flat and groom surface.

Racers inspection will be done on a well prepared surface

How to proceed

Cleaning the snow surface with grooming machine

Conclusion

Questions

Use of grooming machine must be organised and supervised. The magic wand doesn’t work and the key of success is to be creative and using the available tools.

Thank you for your attention