Pondology
news from the waterfront by Tim Matson

A RINK MASTER'S PRIMER

Skating Ponds

Sean Mullen’s pond lies in a hollow at the end of a narrow gravel road in Orange County, Vermont. In winter, the road weaves between snowbanks past a couple of houses and a hunting camp before the ¼-acre sheet of black ice swings into view. Over the past half-dozen winters, the Mullen pond has become a magnet for neighborhood skaters. On most Sundays at about 2 in the afternoon, the air echoes with the clatter of shovels on the rink. A skater slides the goals into place. Then the players toss their hockey sticks into a pile on the ice, and Mullen divides the sticks into two clumps to choose the teams. Another game of Sunday shinny gets under way.

“It started when we had a couple of years with- out snow,” Mullen recalls. “A lot of people around here got frustrated because they couldn’t ski. I made some calls, organized a game, and all kinds of people showed up. I was surprised at how many did. There wasn’t a lot of snow that year, so it was easy to keep the pond clear. The games became something of a tradition after that.”

Winters without snow haven’t become as much of a tradition, so Mullen had to get into the ice-clearing business. He receives a good deal of assistance from other skaters, including a friend with a plow, who helps clear snow after the ice thickens enough to hold a truck. But most of the work is up to Mullen and his wife, Julie.

A snowfall of a half foot or so means three to four hours of clearing for Mullen, using his tracked 5-horsepower, 22-inch snow blower. The blower leaves a residue of snow, so a couple of homemade, handheld pushers with 3-foot blades come in handy to polish off the surface. The Mullens also use steel chippers to shave ice bumps and plane off rough crust. When cracks or frozen slush mar the surface, the Mullens flood the pond and resurface the ice with a portable pump. As the season progresses, the snowbanks around the pond harden and help keep the hockey puck in play.

Skating ponds like the Mullens’ have always been popular in the north country, but there’s been a steady increase in the number of neighborhood rinks since snow blowers and lawn tractors have made it possible to improvise a Zamboni in your own backyard. Still, it’s a slippery and sometimes scary path to the mastery of rinkmanship, as anyone who’s ever heard the thunder of cracking ice underfoot knows. With luck, someone knowledgeable in rink maintenance lives nearby, happy to pass along his expertise. But many pond owners learn the techniques of ice clearing and resurfacing during long, cold hours of on-the-job training.

It snows. You begin to clear the rink. But where do you put the snow? it’s tempting to keep the cleared area small—perhaps just enough space for some figure skating; if a larger rink for hockey will be needed later, maybe let the more ambitious clearing wait. But it doesn’t work that way. Snow piled on the ice bonds to the surface, settles, and hardens. After a few days, it is difficult—if not impossible—to remove. Meanwhile, perhaps more snow has fallen. The snowbank around the rink perimeter grows. It snows again. If you’re shoveling by hand or using a tractor with a plow blade, open ice shrinks as the new snow piles up against the banks. A snow blower can maintain a cleared space only as long as the banks remain low enough to permit the snow to be blown over the top. In a winter with a lot of snow, the skating surface can disappear.

The cardinal rule in maintaining a skating rink is to begin by clearing as large a space as you can manage. If it’s feasible to remove the snow from the ice completely, all the better. Not only will a heavy snow load bend the ice and cause cracking, but also ice under a thick layer of snow is insulated and tends to warm up, melt, and seep on the rink. If the snow can’t be moved off-ice, a good rule of thumb is to push the rink perimeter back 20 feet beyond the area you want to keep clear. That provides plenty of space for subsequent snow removal.

In determining the rink size, it’s important not to make too much work for yourself. If you’re clearing by hand and can count on fellow skaters for help, you might be able to maintain a rink large enough for a hockey game. A full-sized rink is 85 feet by 200 feet, but a 60- by 150-foot rink provides enough space for play. Figure-skating rinks can be smaller. My own pond is about 45 by 90 feet. That’s too small for hockey, but it’s ample for general skating.

The problem is that clearing a rink of any size gets old pretty fast, especially when a fresh snowstorm blows in on the heels of a big clearing job. That’s when the snow blowers, tractors, and plowing trucks come in—and sometimes go through.

Before beginning any kind of mechanical clearing, it’s essential to know if the ice is strong enough to support the load. In general, 2 inches of ice is considered safe for one person, 4 inches for a group of up to a dozen people, 6 inches for a snowmobile or snow- blower, and 10 to 12 inches for a truck with a plow. But the strength of the ice depends on quality as well as thickness. New, clear ice may not cover a body of water uniformly, especially over springs and near inlets and outlets. Thicker midwinter ice tends to be more uniform, and 12 inches will support large groups of people and plowing equipment. Yet in spring, warm winds and sun can weaken ice that is more than a foot thick, making it extremely hazardous. Ice will also be weakened by prolonged weight in one spot, as well as by “resonance waves” produced by a moving vehicle. In other words, ice is complicated stuff, and thickness should not be considered the only criterion for safety.

In case of a breakthrough, one of the best rescue devices is a light ladder with a strong line attached to one end. The ladder can be shoved out to the person in the water, then hauled in. The ladder helps distribute weight over a large area. A ring buoy on a rope or even an inflated inner tube can also be used. For self-rescue, ice boaters and others who may be alone on the ice often carry a pair of awls to help pull themselves out. At the very least, a skater ought to carry a knife for the same purpose. Anyone driving a plow truck on ice should make sure the door opens easily and should keep a window open.

 

  

 

 

As the ice thickens at the start of the skating season, first skaters and then snow-removal equipment can be supported. The lightest machine is a snow blower, so it’s the safest for early-season work. Because of its light weight and ease of operation, the snow blower is perhaps the favorite pond-clearing device. A 5-horse power blower with a 22-inch cut weighs less than 300 pounds. A 36-inch, 11-horsepower blower weighs about 350 pounds. experienced snow removers favor cuts of 32 inches or longer to reduce clearing time. it may not take long to clear a path between the house and the garage with a small machine, but try opening up a ¼-acre pond some subzero afternoon, and you’ll appreciate the extra inches you gain on each pass with a larger snow blower. Besides, the bigger the blower, the farther it throws the snow.



Sean Mullen begins a snow-blowing operation with a pass down the middle of the rink and then works his way out to the edges. “Powder snow will throw about 20 feet; wet snow is like lead,” he observes. “One time last year, when it was about 32 degrees, I used the blower to get the snow into windrows, and then people used pushers to move the snow off the rink. I don’t think I could have done it with the blower alone.”

Pond owners looking for quicker clearing favor small, lawn-type riding mowers or tractors or trucks equipped with a plow blade. A two- or three-hour snow blower job can be handled by a plow in half an hour. But because the plowing rig’s extra weight, it may be unsafe to bring a truck or tractor on the ice as early as you could a snow blower. And there are many winters when you can’t wait for thick ice to begin clearing operations. If the first snows aren’t removed promptly, the skating surface may remain buried. Besides, a plow may not be able to push heavy snow without using chains, which would mar the ice.

Whatever the means of snow removal, after the initial clearing a residue of snow remains to be swept or scraped away. One of the best tools for this is a home- made pusher incorporating a 3-foot plywood blade with a metal edge and a 7-foot handle. I find that a double handle works even better. In the hands of a couple of good skaters, this type of scraper can cleanly polish off a rink in short order, and it can be used every hour or so during hockey games. Clean ice not only means a faster puck, but it also means the cracks stay visible. A skater catching a blade in a crack at high speed can lose his footing and maybe his senses.

Cracks routinely mar the surface throughout the skating season. They are triggered by expansion and contraction of the ice, fluctuations in water level, and deflection caused by the weight of accumulated snow. It is possible to fill cracks with water and allow it to freeze, but the new ice may pop out of the fissures as it expands. A water-and-snow mixture seems to work better, with snow packed into the crevice and water added. Flooding may be required to fix a badly cracked surface or one roughed up by frozen wet snow.

Black ice forms on a pond or lake when the surface freezes without incorporating any snow in the ice. Skating connoisseurs consider this the crème de la crème of ice. Black ice is usually a short-lived phenomenon at the beginning of the skating season, mutating into a blue-white surface as winter progresses. But even a full season of black ice isn’t flawless. Black ice is exceptionally strong, but it becomes brittle with deep cold and fractures readily. Again, flooding is the remedy.

The cardinal rule for flooding is that too little water is better than too much. It’s important to build up the new surface with a thin veneer of ice. The idea is to “grow” the ice upward from the old surface, rather than create another pool that freezes from the top down. Too much flooding often creates pockets of water or air trapped between the ice layers. The best temperature for flooding is a bit below freezing—in the low 20s. If temperatures are too low, the ice freezes unevenly. Sometimes a pebbled effect is created when splashing water freezes during extremely cold weather. And subzero temperatures make the job miserable.

The volume of water required for flooding is usually about 1,500 gallons per ¼ acre. That’s enough to build up ⅛ to ¼ inch of new ice. The water may come from the pond itself, a nearby stream, or the household water supply. Given a generous flow of water through the pond, it’s simple enough to cut a hole in the ice and use a pump. Naturally, the hole should be cut outside the rink area. A pump with a 2-inch outlet is generally sufficient to do the job, and reducing the hose to 1¼ inches makes the volume of water more manageable. The best strategy is to begin at one end of the rink and work backward, so you won’t be walking on the new surface.

Sometimes, if you pump too much water from the pond, the ice sags and cracks. This is not because of the weight of the water on top of the surface; rather, it’s because of the loss of buoyancy from underneath. Then it’s time to find a new source of water. If you use household water, make sure that the water system’s capacity is equal to the volume needed for flooding. One advantage of household water is that it can be applied warm. Indoor skating rinks are often resurfaced with warm water, which creates exceptionally smooth ice because the water melts the old surface before it freezes. You wouldn’t want to heat up enough water to flood ¼ acre, but it takes only a few hundred gallons to put a slick new surface on my ⅛-acre figure-skating rink.

Cracked ice is not the only reason for flooding a rink. “Wet snow means you have to flood,” Mullen says, because the snow bonds to the surface of the ice and makes it rough. Short of a complete resurfacing, flooding is also good for touch-up work in small patches, and it helps to level uneven ice. Flooding even makes it possible to have a skating rink when you don’t have a pond.

adapted from Earth Ponds Sourcebook, Second Edition, by Tim Matson

 


December 1, 2013


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