Articles

The maddening war against permafrost

IT COVERS HALF OF CANADA. It can topple forests and swallow airfields. We’ve licked snow, cold and ice but we can’t beat this. Can we learn to live with it?

BILL STEPHENSON September 14 1957
Articles

The maddening war against permafrost

IT COVERS HALF OF CANADA. It can topple forests and swallow airfields. We’ve licked snow, cold and ice but we can’t beat this. Can we learn to live with it?

BILL STEPHENSON September 14 1957

The maddening war against permafrost

Articles

IT COVERS HALF OF CANADA. It can topple forests and swallow airfields. We’ve licked snow, cold and ice but we can’t beat this. Can we learn to live with it?

BILL STEPHENSON

Ever since tile cold war settled in, Canada’s interest in her own northland has warmed so much that communities and installations undreamed-of a decade ago are fast speckling the Arctic emptiness. In reclaiming her neglected territory, however, Canada has come into conflict with an older, colder foe than any Red, one which she must defeat—or join—if these new communities are to last.

This enemy has been with us always, but only in 1943 was it given an English name: permafrost. The Russians call it vechnaia merzlota, or “perennially frozen ground.”

By any name, permafrost is a slumbering giant, which, if disturbed, may topple city blocks like children's blocks, cause whole forests to stagger drunkcnly or fall, swallow airstrips, roads and railways, abruptly flood houses, bring all summer traffic across it to a shuddering halt, and make commercial and military operations in the north hideously expensive.

Permafrost underlies about one fifth of all land on earth and almost one third of Canada, at depths varying from a few inches in the northern Mackenzie River system to several feet in much of the Laurentian Shield. Its thickness varies enormously with the type of soil and the latitude. As little as five feet of permafrost have been found near Yellowknife. As much as six thousand feet underlie the Anadyr Peninsula of Siberia. Resolute, in our Arctic, can

probe at least 1,000 feet of permafrost, while coal miners at Sveagruvan, Norway, scrape the bottom of their layer at the mine’s 1,050-foot level.

Permafrost so complicates day-to-day living in the Arctic that men and women often see only one way out—leave for a gentler clime.

In most invasions of the north, from the Trans-Siberian Railway in the 1890s to the Alaska Highway, men have sought ways to get rid of permafrost. To this formidable task they have brought fire, the sun’s heat, cold river water and live steam, wheelbarrow, mechanical shovel and bulldozer. The outcome of such attacks generally falls into one of two categories: (1) panic as retreating permafrost takes all man-made effects with it, or (2) permafrost relatively unharmed and man hustling to keep it that way.

Until lately, no one ever seemed to learn from others’ faux pas. The Hudson Bay Railway spent millions in the late 1920s learning to lay track over the permafrost south of Churchill, Man. Yet in 1942 the builders of the Canol pipeline and road from Norman Wells, Northwest Territories, to Whitehorse, in the

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Yukon, made almost the same costly errors all over again.

Today, however, reason seems to be prevailing. In the new town of Aklavik, Northwest Territories, as well as in Nome, Alaska, Frobisher on Baffin Island and a string of anonymous Dew Line posts, governments and corporations are

spending as much to keep from upsetting permafrost as they once did to rout it. Protection, not destruction, is emphasized now, for it has been found that, if treated decently, permafrost can be a firm friend.

Sheltered from the unsettling influences of civilization, permafrost is stauncher

than concrete as a foundation for buildings. Over vast areas where rain is a rarity, permafrost holds moisture in the soil and prevents deserts from forming. In some parts of the Arctic it acts as a permanent repository for prehistoric plants and animals. In others, it preserves historical relics.

It is so cold and so readily accessible in many regions that an Arctic householder with a pickax and patience can hack himself out a natural deep freeze.

These valuable uses of permafrost have come to light partly as a result of intense research stimulated by an ominous. but obvious, fact: the Russians

know more about permafrost than we do. For twenty years Russia has had a special building code for permafrost zones, while we are just formulating one. Fairsized towns like Yakutsk. Chita and probably others, flourish in Siberia's permafrost regions. Our largest settlement on permafrost is Aklavik, whose permanent residents number barely four hundred.

If developments in Canada’s north are to keep pace with those in the south and in Russia, one fact is apparent. “Coming to terms with permafrost has become a matter of urgent necessity,” declares Trevor A. Harwood, of Canada's Defence Research Board.

In an effort to come to terms, we've learned a lot about permafrost in the last few years. We know, for example, that it’s not a substance in itself: rather it’s a frozen, granite-hard condition of any soil or mixture of soil, usually protected by a thick mat of organic material called muskeg. Permafrost differs from the seasonal freeze-ups of the southern half of Canada in one important respect: permafrost never thaws.

In Canada the continuous permafrost line creases the tip of Ungava, dips below the western bulge of Hudson Bay and thence runs northwest to Alaska just north of Whitehorse. South of this line it may appear in sporadic patches in areas of fine sand or clay. The whole permafrost zone, however, is believed to be retreating several hundred yards northward each year.

Russian records confirm our observations of this warming trend. Wells dug for the city of Mezen, Siberia, in 1837 all bit through permafrost. In 1933 engineers had to go forty kilometres north of Mezen to find traces of it.

Recent tests have shown that there is a condition known as “dry permafrost”— that is, permanently frozen soil or gravel containing no moisture. This type of permafrost is no trouble to man. If it should be disturbed, it keeps its shape and solidity. Not so the permafrost in clay or fine silts. These may contain up to six times as much water as solid matter, usually in layers of ice known as “ice lenses.”

If wind, fire, flood, building heat or bulldozer should expose this wet permafrost to thaw, the bottom literally drops out from under. The permafrost shrinks to a fraction of its former bulk and the ground becomes a soupy mass of mud.

At Norman Wells a central heating plant was erected in 1942 with little thought for the permafrost only inches below in the wet silt. Almost at once this began to thaw. By summer the supports of the plant were so undermined that nine-inch cracks gaped in the floor. Four years later, in spite of constant repair work, it had to be abandoned.

It does not require the steady heat of boilers to upset permafrost. So sensitive is it to temperature changes that the rrere shadow of a building may affect the permafrost level of an entire area. During the war hangars were built facing south at such eastern Arctic bases as Frobisher and Chimo. Reflected heat from the sun melted the permafrost over a wide area in front of the buildings, while in the cooler shadows cast by the buildings the permafrost level rose, taking the side of the hangars with it.

It was only an accident of geography that the 1,670-mile-long Alaska Highway rarely broached the permafrost line or it might not have been finished by November 1942. The fewtimes engineers did encounter permafrost in the Canadian section enabled them to recognize the type of terrain in which it was most likely to occur. Thus, by the time the road slashed into Alaska where permafrost occurred more frequently, they were able to avoid it almost entirely. If they could not. they resorted to tactics that have since become standard procedure in the north: root out the permafrost to depths of ten feet, or more if necessary: fill with coarse gravel and allow to refreeze. Then, and only then, ky down your road, your hangar, your airstrip, your heating plant.

This method, which is known today as the “active" approach to permafrost, is generally employed on permanent installations such as radar towers, railways, bridges and large buildings. But though efficient, it is time-consuming and costly. For homes or larger low-cost temporary structures, several “passive" methods have been developed at the Norman Wells field station of the Building Research Division of the National Research Council of Canada.

The simplest passive method for building on permafrost is a framework of logs called a “mudsill.” Heavier structures usually are placed two feet up on piles, which are sunk into the permafrost by an ingenious technique known as “steamjetting." Hollow pipes are driven into the permafrost under pressure of fifty to eighty pounds of steam. This quickly thaws about a foot all around the pipe. Wooden posts, sometimes greased or tar-papered to resist the upthrusting tendency of the permafrost, are then driven in butt down and left to refreeze solidly before the weight of the building is put on them.

Either of these methods can be used effectively, according to John Pihlainen. a Montreal-born Finnish engineer who is in charge of the Norman Wells field station. (Because of his occupation and the difficulty of pronouncing his name, he is known throughout the north as “Johnny Permafrost.") But there is a still better and cheaper method.

"If you choose your site carefully enough, looking for rock or coarse gravel for your foundation, you may build with complete disregard for permafrost and its headaches," says Pihlainen.

Skating oil muskeg

This approach is not always possible where a building or town must be erected on a particular spot. It was used successfully at Uranium City, Sask., how'ever, w'here they laid out the townsite seven miles away from the mine to take advantage of better foundations. And it may be the same approach used by the Russians in operating large settlements in their permafrost zone.

Even if permafrost is not disturbed, it can create difficulties. In summer, w'ater

from the melting upper layers of soil or muskeg gradually seeps down onto the impermeable surface of the permafrost, creating an effect not unlike a rug on a polished floor. You can walk across such an area and find it firm underfoot. But try to cross the same space in a truck, tractor, tank or bulldozer and you may come to a slithering halt. No matter which way you proceed, the ground simply edges away from under and your vehicle remains where it w'as.

"If the first tractor in a line can cross, generally all of them can,” says Defence

Research Board expert T. A. Harwood, “but usually they all bog down.”

Outside of sticking to good roads, which are difficult to build, or using aircraft, there is no known solution to this vexing dilemma of how to move material across permafrost country in summer. This fact alone has undoubtedly added millions to the cost of military and commercial enterprises in the north.

Permafrost is the main reason w'hy Aklavik is being moved from the Mackenzie delta to a spot thirty-five miles east on the mainland known as “East

i". Nowhere on earth, probably, is permafrost more in command than in the spongy silt of old Aklavik, where it reaches to within four or five inches of surface in many places. An attempt to bulldoze an airstrip near the town resulted not only in failure but in the loss of the bulldozer as well. It sank slowly into the disturbed permafrost, and no other machine could be risked to rescue it.

There are the dramatic things, but other aggravating problems and inconveniences caused by permafrost are felt

every day in every home in old Aklavik, At many outposts such as Churchill, Norman Wells and Frobisher ingenious insulated conduit boxes called “utilidors” arc used to convey water, sewage and heating pipes to their destinations. The idea is that the warmth from the heating pipes is just enough to keep the other two pipes from freezing. But utilidors are not used in old Aklavik, mainly because the cost of installing them about the scattered town so that the permafrost under them would not thaw and upset the whole system would be pro-

hibitive. In summer, because of the permafrost so close to surface, all water is delivered by pipes simply laid on the ground. Winter supplies come from blocks of river ice dumped daily into a barrel in the vestibule of each home.

Since septic tanks are costly to dig and maintain, and decomposition is very slow anyway, human waste must be carted away and destroyed. Household waste simply empties into open ditches running past the houses.

"It's quite a shock for newcomers to see the dishwater they throw into the

sink just pouring out onto the ground below the kitchen window,” says Mrs. Bert Wallace, wife of the manager of the North Star Inn.

Cellars arc somewhat of a rarity in silt-based centres like old Aklavik, partly because of the difficulty of digging them and partly because of the unsettling effect they have on the houses themselves.

At such places as Nome, Whitehorse and Dawson City cellars are more commonplace. In parts of these settlements the permafrost may be as much as fifty feet below the surface, and it takes about six months for the deep cold of winter to reach it. Thus in spring, while the surface is warming up, the depths are getting colder. This is true in southern communities as well. Deep water mains in Winnipeg have been known to freeze up in June. Conversely, in the late fall the heat of summer is just starting to penetrate the depths.

These constant changes between the upper and lower layers cause movement, often quite unpredictable. Buildings in Dawson City, for example, lean at an angle and must have their foundations repaired every two years. Cracks appear overnight as the houses tilt this way or that. Many homes in Nome have plates on the bottom of the doors, which can be raised or lowered as the house shifts.

Ordinary seasonal frost heaves, aggravated by permafrost which will not allow the collected water to run off, have been known to snap oil lines in homes, bringing the threat of death by freezing to whole families.

The good effects of permafrost are most apparent on the tundra, that vast area of Canada where the rainfall may be as little as two inches per year, compared with forty in Montreal and fiftyseven in Vancouver. Here, though the air is cracker dry, pools of water dapple the sour earth, animals abound, and in summer the earth is a gay riot of color.

“Were it not for the permafrost . . . preventing surface water from penetrating to depths beyond the reach of plant roots,” explains Dominion Botanist A. E. Porsild in his book Plant Life in the Arctic, “most of the Arctic zone would be a lifeless desert.”

In the western Arctic, where permafrost underlies the forest, it is generally the trees with shallow root systems—such as aspen, beech and paper birch—that survive. White spruce may grow more than a hundred feet high where permafrost is only two feet down. High winds or earth movements sometimes capsize whole areas of these unstably based trees, causing what are known as “drunken forests.”

Permafrost’s value as a treasure house of prehistoric plants and animals is unquestioned. In Alaskan deposits, twentyseven different plants and twenty large mammals have been found, along with rodents, mollusks and even sponges. Curved mastodon tusks have long been tourist souvenir bait in Dawson City. In 1901, during a flood near SredneKolymsk, Siberia, the almost whole body of a young male mammoth melted free of its permafrost tomb and floated to the surface, terrifying the inhabitants.

“The flesh was soft, looking like boiled meat,” runs the report of the Academy of Sciences of St. Petersburg (now Leningrad) where the find was shipped. “The dogs ate it greedily.”

At Naujan, on Repulse Bay in the Northwest Territories, permafrost has also preserved boots, bone utensils, leather, grass mats and even blubber left by early explorers and inhabitants of our Arctic.

Occasionally, permafrost may be a

help and a hindrance to man at the same time.

Permafrost overlay, averaging fifteen feet but up to a hundred and fifty feet deep, kept Yukon gold-rush miners from reaching pay streaks of the precious metal on the ancient bed-rock. At first they tried using the heat of the sun to melt the permafrost, which they shoveled aside. But this was too slow, so they changed to wood fires, heaping the faggots during the long winter nights, clearing the thawed earth by day.

If they were smart and melted only narrow shafts down to bedrock, the very permafrost that had blocked them from their goal now helped them, keeping the shafts solid and safe without wooden props.

For many years now a four-year operation of brush-clearing, topsoil removal, thawing of permafrost and finally dredging has been used by big companies to obtain gold from the valleys of the Yukon and Alaska. The thawing is spectacular. involving a variation of steam-jetting, but with river water used instead of steam. Cold river water is cheaper than steam and is still warmer than permafrost.

Oddly, the townsite of new Aklavik has returned to the original methods of the Klondike miners to obtain not gold but building gravel. Each summer day shelves of dry permafrost are exposed to the sun's rays, the stones being cleared away next day in a continuing process.

How did it get that way?

In parts of Alaska this trend is being reversed. When the U. S. Navy drills for oil at Point Barrow it now puts refrigerated coils into the soil beneath its heavy rigs to keep the heat from disturbing the permafrost. Similar coils were placed under the addition to the Nome public school last year. This method was used because the three-storey Federal Block in Nome—though set on piles in 1937—has been heaved so badly it must be replaced.

Much of the feverish research now going on is directed toward finding out how permafrost got that way. Was it formed, as some authorities say, by the same intense cold that ages ago sent the glaciers trundling down across the land? Or is it a weather phenomenon, occasioned when two or more cloudy summers are followed by cold winters, creating a reserve of cold in the ground? There is evidence to support both these theories.

Most scientists agree that the glaciers did not cause permafrost to form. While the glaciers were present the ground was protected from the cold air above.

Some of the other phenomena connected with permafrost are intriguing. In many parts of the permafrost zone, for example, the ground displays distinct polygon-shaped patterns, often up to three hundred feet each in diameter and plainly visible from the air. What causes these to form? And what causes the “pingoes,” strange mounds of pure clear ice fifty to a hundred and fifty feet high? One of these in Siberia is so old that the remains of a prehistoric man's campfire was found on its summit.

What causes the submerged lakes occasionally found deep in permafrost? How can layers of unfrozen earth exist in permafrost? These layers, known by their Russian name talik, frequently have springs and streams flowing through them. Parts of Nome get their water from such springs, which bubble up warm, mineral-filled and delicious.

Other springs exhibit a playful tendency, rising to the surface unexpectedly

if a bathhouse or home should melt the restraining permafrost above them. At Omootnaya, Siberia, in 1939 such a spring broke free of the talik and suddenly shot upward, engulfing a house and freezing solidly in a matter of minutes. When the logs were pried away a perfect replica of the house in solid ice was left.

More practical but important questions nag at Canadian scientists: where exactly does permafrost occur? How many feet per year is it retiring in, say. Hay River, on Great Slave Lake? What spe-

cific ground conditions dictate that one lot in Yellowknife should be bothered by permafrost underlay and the next one be free from permafrost? Above all. how can you be sure it is permafrost below where you want to build and not just seasonal frost?

Twenty years of test borings may be necessary before the first three of these questions can be answered. But new methods of determining the presence of permafrost could make the whole program easier. Such principles as seismic refraction, gravity profiles, electric re-

sistivity and others are being investigated here, while undoubtedly the Soviets are trying others. Somewhere, soon, someone may turn up a portable permafrost detector as simple to use as a Geiger counter.

If this should happen, will Canada then be able to control her permafrost the way the Russians appear to be controlling their vechnaia merzlota?

The Russians have a phrase that covers this eventuality. It is kto znayet? — which roughly translated means, “Who knows?” if