Technical Resources
Tips and Tales From a Lone Groomers Perspective
I believe that quality ski trails are as important to the sport of cross country skiing as pavement is to drag racing. The purpose of the following information then, is an attempt to bring together and share some practical information about grooming cross country ski trails and to start to build knowledge and skills in the grooming process for all to share for the good of the sport.
Since the winter of 1990 I have been logging in an average of 2000 km per grooming
season in an area where the conditions vary from almost no snow all season to when it just won't stop. The site is located just east of Edmonton, just two miles from the Blackfoot Recreation Area where the Canadian Birkebeiner is currently being held every year, if this helps you to get a visual picture. When learning about grooming ski trails, it seems that no matter how long or how many kilometres experience you have, mother nature always has a trick or two to keep the grooming process entertaining, or you talk to someone with a better idea. The Cross Country Canada "Trail Grooming and Track Setting Manual" was a great reference for all aspects of trail grooming information, and my thanks to all those who have shared their expertise for the use of other groomers to create optimum ski surfaces for their clubs and ski areas.
Over the years, I have found that a good background knowledge in the various aspects of
trail preparations and grooming processes have been my most valuable tool. At one point I was the only groomer at my site and was responsible for fifteen kilometres of eighteen foot wide trails, two instructional grids and a downhill teaching site for daily group ski lessons on top of the general public, the speed of preparing quality ski surfaces was my number one concern. I was always reading, asking questions, experimenting and inventing to make the process easier and faster without sacrificing quality. I would like to discuss what I believed to be the most relevant aspects of creating optimum ski trails, as I understand them to be, and pass on my experiences to those who may benefit.
Pre-season trail preparation
I like to say that you can always walk on a ski trail but not necessarily ski on a walking trail. There is nothing worse than trying to set a quality track on a rocky, bumpy, stumpy, hole filled or sloped trail surface. In some areas where it snows up to your armpits every year, a groomer may not know what am talking about, but those of us who have to deal with frequent low snow conditions can relate. The smoother the trail surface is, with all the proper slopes in place (no negative slopes please) the less snow you need to begin laying down what I call the pre-base. This pre-base is where I try to compress the first few inches of snow into an icy sheet over the entire trail system in an attempt to form a thermal blanket between the warm ground surface and the cooler ambient air, and to trap and freeze into this blanket all the little sticks and gum wrappers that were missed when you first tried to clean the trail. This often happens when the trail cleaning volunteers get tired after snipping and clipping the overhanging branches.
The Physics of Snow
Studying the science of snow morphology is a worthwhile bedtime read. This information is valuable to understand because the use of it should preclude your grooming process. It's a good idea to have prior knowledge of what typically happens in your area where it relates to average snowfall accumulations, air temperatures and the periods your area experiences with thaw-freeze cycles. This information is useful in what I call snow management, a topic that I would like to expand on. It is also understood though, that a lot of us do not have the luxury of grooming" when the time is right ". We generally groom when we either have the time, have the manpower or have to groom because of public demands.
Grooming at night is not always necessarily the best time to start the process as far as temperature, snow condition and humidity are concerned, although it is the most convenient time as groomers and skiers have a better chance of not interfering with each other.
Understanding snow physics will at least be helpful in predicting an outcome under these conditions.
Snow Management
What is evolving in the general area where I groomed, was an ever expanding population of skiers looking for the best conditions possible for their favorite ski technique. One area close by is known for it's quantity of good skating lanes and race training, while another is more suited to the long distance in solitude experience in a formed track. Further down the road is a site where the backcountry enthusiast will be drawn to. All of these Nordic experiences are of equal value, so it's important to know who is using your trails now and how should you be grooming to best accommodate their needs. You can also ask yourself, how can I serve the present skiers while trying to attract the up and coming future skiers. Lets face it, not all of us want to cross that frozen lake in a windstorm, or wear the tight spandex suits while screaming down the steepest hill we can find. In short, try and decide who you have to cater to in your area and how to best groom the trails for their enjoyment.
At this point, I would like to share my grooming experience with those who may find it of some use when grooming in their areas in similar conditions. This experience has been gained by grooming with snowmobiles and pull - behind grooming equipment only. Please take this into consideration when reading further on.
Grooming for the Ski Skater
Most of the people I know that use this technique, are very good at it and need excellent conditions to train and race on. I believe the most important aspects of the snow base to a skater is a consistently uniform snow density, a smooth and ridge free surface to dig edges into and the skating lane to be wide enough to allow them to stretch out at their top speed. Some grooming manuals suggests that a skate lane should be at least at eight feet in width, but I have found that a good skater will hog up to twelve feet or more if they have the room, at top speed. This of course will depend on the terrain that they are skiing. I have allowed a ten foot wide skate lane at my site and I see a lot of happy faces. There is certain amount of discussion revolving around the crowning of skate lanes as of late. On some of the steeper uphill climbs, some clubs are grooming a fairly high crown in the middle of the lane. The theory is that with a prominent crown, your skis are being pushed downward as well as out, so it gives you the feeling of skiing downhill. After talking with some of the experienced racers in the area, they say that it is much easier on the body to skate uphill on a track groomed this way, but you will sacrifice speed because of the shorter leg stroke. They also say keep the flats and more gentle hills level and flat as possible. Remember to pay particular attention to this density thing, because a skater will rely heavily on a solid polling surface as well. Soft spots in the snowpack are extremely irritating when you hit them with a pole or ski and they can throw you off balance. The manual suggests that the snow density should be at least a .5 (kilograms/cubic meter) for a solid skating surface.
Grooming for the Classical Skier
For this technique, what has been discussed in grooming manuals regarding ski lines, distances between the tracks and the track and edge of the trail are good standards to go by. What I have discovered where I groom however, is that a two foot comfort zone between the track and the bush line is a little too close for a lot of our type of skiers we have at my site. The duffers and beginners appreciate more area to" step to the right" to let other skiers go by. They also like more area to fall on and swing their poles as they attempt to keep their balance, break into a snowplow or herringbone right up the middle of your nice tracks.
I tried to adjust the snowpack densities to accommodate the variety of trail conditions that I need on the same trail. For instance, I would groom the edges of the trails first and then the center, to try and keep all of the snow on the trail. I paid attention the number of times that I go over a section and try to keep the milling or " mechanical aging " process to a minimum but aiming for the desired density. The manual suggests that a good classical track will have a density of around .45 (kilograms/cubic meter) for moderate use. At the site I groomed at, we were basically a family use and teaching facility so I tended to reduce the classical tracks density to as low as .28 (kilograms/cubic meter) in a fresh snowfall. I found this satisfactory for us because of the number of novice skiers on the trails using our no - wax skiis find it easier to fall on (and they do that a lot) and I am able to keep enough air in the snow base to recondition the tracks much easier the next time. Of course, every time the base is groomed the density will increase, whether I wanted it to or not. I would make more passes over the skate lanes to achieve that .5 (kilograms/cubic meter) density. If could get close to these standards of densities during the week I was happy, On the weekends however, we saw a lot more use from the general public and after grooming over the trails that the grade five ski classes have used, the densities on the classic tracks are reaching around .35 to .4 (kilograms/cubic meter).
I realize that in a lot of areas, some of these standards (4 ft between classic tracks, 4 ft comfort zone between the tracks and the bush line and a 10 ft skate lane) cannot be achieved because of different regulations and guidelines in the area regarding land base conservation efforts will limit trail design. Other factors effecting the trail design and its' maintenance such as manpower, financial challenges and a multi - use understanding of trail use are all factors that determine the size and quality of skiable trails. However, there are a few grooming techniques that can help you to maximize the quality of trail. The first one I became familiar with was to know the limits of my grooming equipment and what was a realistic goal to achieve when trying to produce that postcard perfect trail surface. Another factor I had to deal with was how to groom over long periods of time and still concentrate on producing the same kind of ski surfaces that I did in the beginning of the day. Some of the more useful operating skills I developed was to learn how to operate the snowmobile without it beating me up. Using your weight for leverage when turning, as light a grip as possible when steering, keeping the speed down (it makes for better tracks and combed finish anyway) using a kidney belt if you have one, hearing protection including the helmet (if you use one) and trying to track downhill on the steeper hills instead of uphill if possible (also makes for a better track because you can use a more constant speed and you don't have to hang on to the handlebars at warp speed going up those hills) are some of the techniques I use constantly. I again realize that many of you would not be required to spend as much time grooming as others, but why not try and make it as fun and safe as possible.
So here you are, on the machine and loaded down with knowledge and equipment, on
your way to completing the first kilometre of pristine trail when that grade five class full of vigor enters upon the trail system just behind the Senior Duffers Ski Club. What we really need here is HUMOUR. You have to realize that these people are out enjoying the tracks you just made and have never heard of set up time, and what they leave behind is of no concern to them. After a few years of wishing to be able to run them into the bush and keeping myself frustrated, I learned to groom around them. Often, instead of trying to groom a complete trail for them to its' full width, I would groom only one side of a greater length of trail and then switch to the other side, realizing that I would have to come back and re-track set after the crowd had left and were not likely to come back that way for sometime. In other words, after having completed one set of tracks for people to enjoy I would try and follow them instead of them following me. It actually works a good deal of the time! Keep in mind that your last pass should be the best one, and maybe the tracks will have enough time to set up and then last for awhile.
This works well for the general public and the beginner skier, but if you are grooming for a race it becomes a little more difficult. Attaining the proper densities are very important. Timing is everything, and good grooming conditions do not always correspond with people on the trail system. You should work out a good grooming plan before you begin the grooming process for your area, and it will help you keep your HUMOUR.
Grooming for Instruction
My train of thought is this. If the trails are good enough for the expert skier, then they should suffice for the beginner. I believe that the quality of the ski tracks on the trail as well as the instructional grids should be of superior quality in order to help a beginner with their balance along with their kick and glide as much as possible. The teaching grid should include a flat packed area of sufficient size to accommodate the playing of various games by students with their skis on without being crowded. This area is important for the students to become familiar with balancing on skis and to realize that their skis are not glued to the snow! The grid lanes themselves should be of sufficient length (we have seventy five meters for our long grid and a forty meter grid for the little guys) to allow the instructor to properly analyze and help the skier with their technique before they head out on the trail. I'm personally not too worried about the lanes being absolutely straight or exactly four feet apart. What I do is try and use that distant focal point to site on when I make my first pass, which becomes the furthest outside track. Travel beyond the end of the grid and take a look. If the track is really out of whack then tum around and recut the track on the way back. When you are satisfied with the first track, tum around in a long enough arc where you can be going in a straight line as you hit the end same end of the grid again, but far enough from your first track to what will be the center of the grid. Try to stay parallel with the first track (the hardest part of grid setting for me). Again, go beyond the far end of the grid and begin your arc again trying to hit a point about four feet parallel to the first track. At this point, I focus on staying the four feet all the way down by watching the track and the tip of the snowmobile ski as reference points. Continue the process until you have all your tracks in about four feet apart. It's better to have tracks a little further than four feet apart then closer than four feet. If you have trouble following this process, then head over to the nearest hockey rink and just do what the zamboni does. I've never had any instructor complain to me that the tracks were not straight, only if they were washed out. Remember that the idea is to give the beginner conditions that will show him the best time possible while helping them learn proper ski techniques. After all, they may become good groomers someday!
Grooming For Results
Now we know what we need for the skiers, but what about us, the groomers? We all know that generally, the groomer is the unsung hero of the trails. For those who are relatively new to grooming, I would suggest that you seek out as much information on the various kinds of equipment that is available by talking to other experienced groomers in the area, or even visit other sites if you are able and see what they are using, what works and what doesn't . Different areas will have more need of specialized equipment than others, and it depends on the quality of
trail they are aspiring to, the climatic conditions they have to deal with and the available manpower.
Packing
There are a number of ways to pack a trail. The most common way in the early season is the snowmobile itself. The idea is to pack the snow evenly across the trail trying to achieve a constant density .
If your trails are rough and full of irregularities it is necessary to pack in narrow widths to allow the snowmobiles tracks to compress snow into the depressions. This will help to eliminate soft spots in the snow base. As snow falls, you will have to decide how deep you want the snow to accumulate before you repack. Packing or often means that you will get a good solid base to skate on or press tracks into, but keep mind that the more you work with the snow the faster you age it, and old snow is harder to work with. This is where your snow management plan comes in along with some experimentation with densities. As the snow base gets deeper and flatter you can start to use a commercial packing device. Keeping the packing speed down to around the ten miles per hour will help keep the snow on the trail and will result in a better base. The basic packing equipment in our area is either the snowmobile itself, a roller made out of expanded metal or culvert section, or a flat panned compression device. A flat pan system is designed to pack the same way as a compression bar on a snow cat. The snowmobile works well, but because of the narrow packing width, takes a long time and levelling is required after a certain period of set up time. The rolling devices pack a wider path but it is important to keep the speed slow so as not to create wash boarding of the trails. The solid culvert type of roller will of course leave a rutted surface that should be levelled out after set up. Some areas use an expanded metal roller which will help mechanically age the fresh snow by the tumbling action of the snow that is thrown around inside the drums and then thrown out. The rolling type of packers are also susceptible to ice buildup on the drums surface in some conditions which leave mini craters on the trail surface. I used either a renovating leveler or a skate lane drag to level with. With the flat pan system you can pack at a faster speed without washboarding and no further levelling is required. The new multi - position levelers have the capability of also aging new snow while packing and levelling at the same time. The skate lane drag does not have the capacity to renovate, but commercial models let you pack up to a ten foot ridge free path in one pass. On all of the packing devices listed above, there is usually a weight carrying system to allow you to compress the snow to what you feel is necessary to create a target density.
Leveling
In order to set a straight classic track, you need to have the trail surface as flat as possible. The smoother your snowmobile can travel over the surface the smoother and straighter the track setter will follow. Again there are a number of devices out there that can do the job. The most versatile ones level the base by cutting the highs and fill in the lows with a grading action. This is the most common device to also mechanically age the snow to achieve desired snow density. A common drawback to some of these devices is that they cannot be dragged through deep snow without bogging down because of the excessive snow buildup, and prepacking is necessary. Keeping your trails as level as possible is not only better for the skier, but also for the renovation process. Besides the track setter, a leveler is your most valuable tool.
Track Setting
I would like to mention a few things to be aware of when building or purchasing a track setter. A good track setter should have some kind of weight holding capacity where the weights you place on will not slide around or fall off. On some trails there are a number of serious side slopes to contend with, and uneven weighting due to the weights shifting on the pan on such slopes can result in uneven compression of the moulding track shoes and a poor track setting job. On some models, the design allows for the track shoes to be lifted off of the trail surface when tracking is not desired. A problem to watch for when considering the devices that lift the rear of the pan up is that it also places the weight to the front of the pan and deep gouging may occur. As well, if the side stabilizing plates are lifted off the snowpack as well, straight tracking may be more difficult. The weighting of the track setter can also lead to interesting discussion. A general rule I followed was that the more weight you use the more the compression, the more the heat generated to the track shoe by friction with the snow, the better the track set and the longer it lasts. However, the more heat that is produced the more icing you will likely get on the bottom of the track pan. There are a number of products that are applied to the bottom of the pans to try and reduce icing, but I found that a polyethylene sheet attached to the bottom of the pan has worked best for me in the area where I groom. I typically used about two hundred to three hundred pounds in most conditions, but you will have to experiment with the amount of weight you need at your site to achieve that desired density of the track set and polling lane itself.
Renovating or Reconditioning:
After a certain period of time, the trails will become too dense to re-level or re-cut a new track. This process requires a good deal more pulling power and an aggressive track ripping tool. The idea here is to be able to rip up iced coated or super dense snow base into fine particles again to allow for the mixing of new snow into the base to reduce base density or retrieving better snow from underlying layers in the base. The finer you can break down the unwanted layers during the first pass the less work there is to do. Some devices break up the snow effectively but leave large chunks that have to be further ground down by the use of repeated passes of screen rolls or levelling-renovating devices. A further problem occurs during this process, but affects the steering capability of the snowmobile. When pulling hard, a good portion of the snowmobiles weight is transferred to the rear of the track which lightens the front ski making it difficult to steer, especially uphill turns. To resolve this, some manufactures of grooming equipment have developed specially designed traction hitches to more evenly distribute weight over the tracks and keep the front skis weighted when pulling grooming implements.
I am hopeful that the art and science of grooming will become a more recognized as aspect of the cross country ski experience. In the meantime, don't be afraid to experiment and keep on sharing ideas.
Rick Potts,
Previous Owner, Advance Track Setting Systems
