|Strategies for Dealing with Low Snow
The 2011 Sprint Course at Black Mountain of Maine in Rumford
When Mother Nature fails to deliver bountiful snow, races are often held on a surface that resembles a dirty ice rink. Artificial snow, old snow, dirt, ice and moisture stick together in a weird conglomerate that can be very challenging for wax technicians. Athletes are forced to train in less than optimal conditions, stressing them physically and mentally. Given the dearth of snow in North America this season and the very likely chance that the US Nationals will be run on mostly man-made snow, we thought it would be good to put together a skier's and service tech's guide to dealing with low-snow conditions. We've put together this guide to ski selection, structure and waxing.
About "Snow" in Low-Snow Conditions
There are a couple of useful things to know about the track that you're skiing on when conditions are less than optimal. When the snow is thin mid-season, it is usually a mixture of old, greasy, fine-grained snow, man-made snow and ice with significant dirt thrown in for good measure. All of these require special considerations in order to produce fast skis.
As snow ages, the sharp crystals that define fresh snow tend to soften with freeze/thaw cycles as well as the mechanical fracturing caused by grooming and skiing. In other words, skiing over and grooming snow breaks it up into smaller pieces and breaks off the delicate features of the the iconic snowflake. Fine-grained snow tends to get greasy and glaze easily because the snow crystals lose their ability to soak up moisture and hold it in the snowpack. It also requires different wax, ski and structure choices.
Man-made snow varies wildly based on the conditions when it was made, the equipment and chemicals used, as well as its age and application method. Generally, artificial snow is very aggressive and looks more like large ice crystals stuck together than snowflakes. Because of the high ice content, man-made snow requires special considerations for durability of kick and glide waxes, as well as structure.
2011 US Nationals at Black Mountain
Dirt is a very important consideration when dealing with these conditions. As snow melts, all of the dirt and dust that have collected in the snowpack are deposited right on the surface. Grooming and moving snow around, especially when there is not a lot of snow available, also introduces huge amounts of dirt. Dirt particles stick to wax and structure on the ski base and then drag through the snow as you ski. The more dirt on the ski base, the more drag slows you down. Keeping skis clean will have a very large effect on ski speed, especially toward the end of a race. These snow conditions generally require aggressive structures, but choosing the best structure will require finding something that is fast, but also minimizes dirt accumulation. Softer waxes may be faster initially, but they tend to attract dirt faster than harder waxes, so dirt affects how you should choose your glide and kick waxes.
Generally, the snowpack in low-snow conditions is hard, icy and dirty. For skate skis, a stiffer, more stable ski is generally going to be the better choice. In many conditions, stability can reduce speed and for top-level racers, the trade-off is not worth it. When conditions get hard and icy, though, even elite skiers will be better off sacrificing a little speed for stability and edge bite. You can generally choose a ski that is stiffer and higher camber with a "tight" tip that will help steer the ski and provide extra edge bite.
For classic skis, having a stiffer, higher camber ski is the ticket. You will need to protect the kick wax from the abrasive snow for durability and keep sticky grip waxes off the snow to keep the ski gliding fast. Whether you are running hard wax or klister, make sure that you have a fairly high camber, punchy ski. A klister ski will need to have a higher camber and be stiffer than a hard wax/binder ski, but either way, make sure that you have plenty of clearance in the kick zone.
The Black Mountain Race Crew Making the very best of the snow available, Nationals 2011
In general, treat old snow as if it was a grade warmer than the temperature suggests. Because the old/manmade snow crystals can't absorb much moisture, the snow will act "greasy" and be quick to glaze. This extra free moisture needs to be handled by the structure, so old-snow structures are typically more aggressive than the equivalent new-snow structure for the same temperature. Cross structures tend to work well on hard-pack, icy, old snow. At the same time, we need to balance moisture handling with dirt accumulation issues. Sharp, deep and busy structures are more likely to collect dirt than duller, shallower and simpler structures. Dirt accumulation can dramatically reduce ski speed over the course of 10km+. When possible, test out structures when clean (freshly cleaned and waxed skis) and then test them again after 5km or so of skiing. It is often tricky to figure out what the best balance between speed and dirt repellency is, but you have to make a judgment and try to keep additional hand structures clean, simple and light. Be sure to brush skis very well with a microfinish steel brush to completely clean out all wax residue from the structure before racing.
Glide wax for man-made and old snow needs to provide extra durability, dirt resistance and sometimes electrical conductivity when compared to waxing for regular natural snow. Much of this is accomplished by using a hard base layer and then choosing race paraffins and fluoro powders that excel in old and/or manmade snow. We have been using SkiGo LF Graphite as our preferred base layer for years as it almost always makes the top layer faster and adds extra durability. The graphite also provides dry lubrication and helps to dissipate static that tends to build up in aggressive snow conditions. Other great hard base layer options would be Start Graphite and Rex RCF Pink.
Once the base has been hardened appropriately, choose a race paraffin that performs well in old snow and is the hardest available. As a general rule in manmade conditions it is best to go one wax colder or harder than you normally would. We like to run a test of 6-8 race paraffins and then ski the top 2 or 3 waxes for 5km and then re-test. This provides information on durability and dirt resistance that might factor into our final wax choice. If one wax is slightly faster at first, but then slows dramatically after 5km, we'll usually choose the second or third option if it is more durable and picks up less dirt.
Moving snow from a nearby backyard onto the race course, Nationals 2011
At the world championships in Liberec, Czech in 2009, the snow was so dirty that the skis were slowing down by 2% or more after skiing them for 2km. This is a very dramatic example of how important dirt resistance can be.
It is almost a certainty that fluoro powders and fluoro liquids will be fast when dealing with old and manmade snow. Fluoro powders not only add speed, they provide the huge bonus of dirt resistance and durability, both vital to having fast skis all the way through a race in aggressive snow. Invest your time and wax resources into testing fluoro powders that excel in old snow. Most brands now highlight the type of snow each wax handles best in addition to a temperature range.
Liquid Fluoro waxes tend to work very well in old, fine, manmade and aggressive snow. While they tend to be not so great with new and average snow, it is always worth testing one or two when the snow is older. We usually apply these over an ironed-in application of fluoro powder and finish by hand-corking with a natural cork. The liquid topcoats can speed up the ski so dramatically that the results are sometimes startling. The SkiGo liquids are our number one choice as they seem to run more often than other brands and when they run, they produce fantastic results. SkiGo liquids were on the winning skis at US Nationals in 2011 at Rumford four times, in exactly the same type of snow as we expect to see this year.
From our experience as wax techs and at Rumford specifically, here are some waxes we expect to be running fast in Rumford for US Nationals. We'll have test results on-site and on bouldernordic.com during Nationals week, so feel free to drop by and talk to us about what we're testing and our recommendations.
Pre-race preparations in Rumford
In general, klister will be used in some form or another in aggressive and man-made snow. Any kickwax application needs to be durable. Ski selection is vital here so that the ski has high enough camber to keep the kick wax from being peeled off the ski by the abrasive snow. But if you have the right ski, you will almost always start with a hardwax or klister binder. Old snow and man-made snow crystals don't have a lot of sharp edges for the kick wax to grab onto, so it often works to put a soft layer of klister or kick wax over the binder and then cover it with a harder shell of klister or hard wax. The sticky wax is needed to provide grip and the shell, or cover layer, releases the snow crystals from the wax, preventing icing and adding glide speed. It is very important to test the kick job over the length of the race to make sure that the wax will wear correctly while performing at optimum over the entire distance.
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