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Science of Grooming
Although the average first day of grooming in Anchorage is November 11th, base development starts in July. As with everything NSAA does, we aim for long-term success and maximum return on our investments.
Step One: Dirt work & tree work. Once the trails are thawed and dry from last season’s snow pack, NSAA crews and volunteers begin preparing the trails for next ski season. Dead and downed trees are cut, limbs are chipped, stumps are removed. Trails that receive our volume of year-round use need an overhaul every 15-20 years. This past summer NSAA worked on several trails in the Beach Lake trail system in Chugiak and the Lekisch 2.9K trail at Kincaid.
Step Two: Grass Mowing. We usually mow twice during summer, once for summer users and one pass after the leaves have fallen. Mulching the leaves with grass will keep the leaf layer from creating an insulating layer or creating a slippery wet layer that will keep the first snow from bonding to the frozen ground.
Step Three: First snow. NSAA’s primary goal is to get the first snowfall to adhere strongly to the frozen ground in a thick base. This year, the first snowfall was delicate and cold, meaning the flakes themselves contained many thin dendrites. There was not a lot of humidity within the base at first, so immediately packing it down might have broken the dendrites and created ball bearings out of the crystals, or sugar snow. However, through natural occurrence, humidity will eventually seep through the snowpack, bonding the snow crystals and increasing the yield.
If there is too much moisture in the snowpack, early grooming can create glacier-like ice. Although we’re all eager to get out there, sometimes patience can lead to the best base. And then the weather throws you a curveball: high winds. Although the snowpack would have been best preserved by patiently waiting, the predicted winds demanded a new approach: groom it down before it all blows away. Thus, our groomers got out there and by hook or by crook tried to save our base.
Step Four: First Packing. Roll it? Squish it? Blade it? The goal is to create a layer of snow with a uniform consistency and depth on top of that well-bonded first section of snow. Again, how much moisture is in the snow pack will dictate the best course of action. The groomers’ goal is to create a bonded, high yield snowpack. This can be done through various techniques, equipment and numerous tools, depending on air temperature, ground temperature, humidity, and weather.
Step Five: Snow Cat Grooming: On average, our Pisten Bullys can groom 50%-80% more kilometers per hour than a snow machine can. Therefore, as soon as the snow pack is consistent enough, deep enough, and completely frozen, we want to put our big cats to work. The critical issue with early snow cat grooming is making sure that the snow does not “flip.” If the base pack is not ideal, the treads of the snow cats will cut through the base and flip the layer of snow as they drive over it. The result is grass, rocks, and dirt on top of the snow. Groomers start testing the cats by driving them in the NSAA operations yard at Kincaid first, and then on flat trails. Often times grooming on flat ground will be fine, but when they attempt a hill, the bond won’t hold and the result is a streak of dirt up the center. This is not the result of “grooming too deep” as we often hear from skiers, but the base layer bond breaking and “flipping over.”
When is it okay to put the big cats to work? This is where 20+ years of grooming experience comes into play, though every season is a learning experience. Often times what works in one area of town (or even one portion of the same trail) will not work in another. More than once our groomers have encountered changed conditions and wish they had a helicopter to haul them out. Instead they must look for the quickest path back to the yard that will minimize the damage they know they are causing.
Step Six: Tracks! Groomers want tracks as soon as they are able to get them in. They need 2-3” of consolidated base (not just snow, but base). Without that there will be a dirt strip on the side of the trail. Groomers try to allow for the maximum amount of time between setting track and skier traffic. But at times with changing weather, the most economical time to groom is early morning. Many times the effects of a night groom completed at 3am are completely nullified by an early morning weather event. Resources are finite and we must ration the labor we have and try to guess and schedule the best time of day to groom.
NSAA grooming staff consists of some folks who have 20-30 years of experience and some that are new to the business. Each one of them will admit they are still learning and that their training ground is our trails. Some snow conditions only come around every few years and even our crew that have been working for several years may have never encountered a particular condition before. Just like doctors, our groomers strive to “do no harm,” and they are content to work with what’s given in all circumstances. Decisions are made with less than ideal conditions to work with, less than perfect weather forecasts, and a finite number of groomers (both human and metal). If every skier in Anchorage were to purchase a pin, we could probably groom as each hour dictated. Instead, we strive to maximize our resources and our effectiveness by grooming at the most economical times.