On Thin Ice

Is It Safe?

By Farwell Forrest
farwell@paddling.net

February 8, 2005

On thin ice. The very words convey a sense of danger, or at least of dangerous uncertainty. "He's really on thin ice out there," we whisper whenever someone grabs at a long chance, and then we wait — smugly or apprehensively — for the Craack! that we're certain will follow. Of course this commonplace expression has its basis in cold fact. The danger is real. Plunging without warning into frigid water, far from shore and help, isn't exactly a recipe for longevity, particularly if the water is moving. To be swept under the ice by a strong current is the stuff of nightmares, after all. But why should this concern paddlers? Isn't thin ice somebody else's problem? Yes and no. Many canoeists and kayakers are also skiers, snowshoers, and winter anglers. If we weren't, we'd be condemned to stay indoors for a third of the year. Even paddlers who never leave the health-club gym from Christmas to Easter occasionally run into ice on early-season river trips. And what about backcountry explorers? Go high enough in the mountains, or far enough north, and you can meet up with ice well into summer. I've been stopped cold on big northern lakes as late as the 4th of July.

The upshot? Unless you paddle only in tropical waters, you'll encounter ice sooner or later. What then? If you can't hang out in camp till the sun does its work, and if it isn't practical to walk around the ice that's in your path, you'll just have to push through it — or trudge over it. Either way, it's a good bet that you'll find yourself walking on ice someday. And when that day comes, the question uppermost in your mind will probably be…

Is It Safe?

Easy to ask, but hard to answer. You can always wait for the first Craack! and then hope you have time to scramble to safety before you break through. A lot of people do this every winter, and — somewhat miraculously — most of them make it back home. Most of them. But not all. Smart folks will look for another way.

The best field test of the potential bearing strength of any ice is to cut a hole through it and check its thickness and quality. One widely-promulgated rule of thumb suggests that two inches of "clear" ice is safe for an unaccompanied walker, treading carefully, while as little as three inches will support a large party walking in single file. The Burlington, Vermont, office of the (U.S.) National Weather Service is more cautious, however, warning that "at least" three inches is required to support one person, with five inches needed for a group. But that's not the whole story. Chopping through even two inches of ice is hard work, and if you want to be safe, you'll need to do it often, maybe as often as every few yards. It's a tedious chore as well as a sweaty one, and for that reason alone, it's a job you're likely to neglect. An ice auger makes the work much easier, but unless you're an angler bent on fishing through the ice, an auger's a perishing nuisance to carry. All in all, digging test holes isn't a practical solution for anyone who's on the move, let alone a paddler who finds ice blocking his way in summer.

OK. How about using the color of the ice as a guide? Again, the experts offer helpful hints. New ice is black, and usually both thin and weak. Thick ice — safe ice — is gray or bluish gray. Unless it's frozen slush, that is, whose milky color could easily be mistaken for gray in the half-light of a typical winter day. Yet slush ice needs twice the thickness of clear ice to be safe. Nor is this the only difficulty. What if there's a foot of snow on top of the ice where you're standing? You see the problem. Or rather, you often won't see it. At best, color is an uncertain guide. At worst, it's a trap for the unwary. And much of the time it's just plain useless.

Luckily, there's a better way. Take a leaf from the unwritten book of the circumpolar peoples, men and women for whom crossing ice was a daily business, as well as a matter of life and death. Get yourself an unaak, short for unaakpaurak or "little harpoon." That's a pretty good description. An unaak is an ice-test probe and self-rescue tool in one. And it's simplicity itself: a long pole with a sharp spike on one end and a big hook on the other. It's simple to use, too. As you walk, thrust the spike into the ice just in front of your feet. If it goes through or feels mushy, STOP. If it bounces back, continue on. Snow is no obstacle, or at least a foot or so isn't. The spike will cleave it effortlessly. To be safe, test the ice every few steps — before each step if your still, small voice demands it. Probe. Step. Probe. Step. Probe. In no time at all, you'll settle into the rhythm. It's almost automatic.

Almost, but not quite. Before entrusting your life to your skill with an unaak, you'll need to practice somewhere safe, in water you're certain is no deeper than your thighs, close to shore and free from any current. It's best to wear a life jacket and have a friend standing by with a sled, a rope, and a change of clothing, too. And until you're very sure of your aim, wear shoes with safety toes. A rubber pac doesn't offer much protection from an unaak's spike. It's not called the little harpoon for nothing!

So far, so good. But where do you get an unaak? You won't find one at the local big-box retailer. In fact, I know of no commercial supplier. So you'll have to make your own. Here's how. Get a hardwood tool handle, one that's at least four feet long. An ash handle intended for a shovel or pitchfork is ideal. Buy a 50d nail — that's a wicked big spike — too. Now cut the head off the spike and drill a two- or three-inch-deep hole in the working end of the handle. You need a tight fit, so measure your bit against the spike before you drill. Next, hammer the spike home till the cut end bottoms out in the hole. Then dress the battered point with a file till it's sharp enough to draw blood. To finish the job, whip the last four inches or so of the handle with nylon twine and coat the lashing with epoxy. (This makes it much less likely that the spike will split out in use.) That's all. You now have a portable ice tester. The rescue hook can come later.

A few variations on the theme: If you can't find a 50d nail, cut the grip off a sturdy screwdriver and use that. (Don't forget to resharpen the point after you're done bashing it into place.) You can also substitute a metal ferrule or several hose clamps for the lashing, if you prefer. And if you're just not a do-it-yourself person, buy an alpenstock, instead — if you can find one. They're almost as rare as unaaks. In a pinch, you can make do with a longish (80-cm or more) ice ax, though you'll find the necessary half-crouch mighty tiring if you have to probe for more than a few hundred feet. But at least the ice-ax pick makes a useful self-rescue tool.

Ah, yes. Self-rescue. That's another subject altogether, and a mighty important one, too. But it'll have to wait till next month. I'll also have more to say about getting around on ice, in and out of a boat. Until then, if you're tempted to experiment, stay close to shore and away from deep water, and don't go alone. Stay safe, in other words.

Snowshoers and skiers aren't the only folks who can expect to find themselves on thin ice from time to time. It can happen to paddlers, too. But a few hours spent at the workbench can make a world of difference. So before you find yourself on the icy margin of some frozen lake, waiting anxiously for the Craack! of doom, why not make yourself a little harpoon of your own? It's a very good point to have in your favor.

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