The Children's Blizzard

by David Laskin

  Woodruff and McAdie began entering the 7 A.M. data on blank maps of the United States—for every station in their network, some forty-six stations in all, they filled in the temperature, barometric pressure, wind speed and direction, and state of the weather (fair, clear, cloudy, raining, or snowing). On the first map, Woodruff used red pencil to draw in the isobars, the contour lines connecting stations reporting the same air pressure. As if by magic, evanescent mountain ranges of high and low pressure erupted across the country in ripples and tongues and irregular concentric circles of isobars. Woodruff could see clearly that the huge elongated high centered just north of the Dakotas that had materialized on the previous night’s map was shifting southeast. A low seemed to be nudging down from the north behind the high, hence the falling barometer at Fort Assinniboine, but Woodruff did not have readings from far enough north in Alberta or Saskatchewan to get a clear picture of what was happening upstream. The high over the Dakotas was nothing out of the ordinary for this time of year, so it was unlikely that anything really violent was pressing behind it. The sharply dropping pressure over Fort Assinniboine might be a freak or an error or a fabrication by a lazy observer. Woodruff had spent enough time in wind-whipped frontier forts to know that the sergeants and privates who staffed these weather stations were none too reliable. And Fort Assinniboine was one of the most remote military outposts in the country—a vast rectangular treeless compound of two-story brick buildings, second in size only to San Francisco’s Presidio, thrown up hastily in the harsh grasslands of northern Montana in the wake of Custer’s disaster at Little Bighorn.

  Woodruff decided to be cautious. Central Montana stations were reporting slightly warmer conditions, and it was a good bet that this mild weather would spread south and east as the high-pressure center continued to move eastward across the country. He wrote out the afternoon forecast by hand in black ink on a slip of tissue paper:

  January 11, 1888—10:30 AM

  Indications for 24 hours commencing 3 PM today.

  For Saint Paul, Minneapolis and vicinity: Slightly warmer fair weather, light to fresh variable winds.

  For Minnesota and Dakota: Slightly warmer fair weather, light to fresh variable winds.

  Woodruff would keep an eye on those Montana pressures when he issued his next set of indications at midnight. Though the press and the public still believed that forecasting the weather was more hocus-pocus—or hoax—than science, Woodruff was convinced that the essential elements were clear and straightforward. If you could define the areas of high and low pressure, identify their centers, and track their movement, you could pretty much predict the rise and fall of temperature and the likelihood of stormy weather over the next day and often over the next two days. As Woodruff wrote in his paper “Cold Waves and Their Progress,” “In various investigations and studies, it has been shown that a fall of temperature succeeds or follows an area of low barometer, and a rise precedes such an area; and that, in general, the reverse is true of an area of high barometer, viz.: that a fall precedes and a rise follows it.” In other words, temperatures rise in advance of an approaching low-pressure system and fall once the low has passed, while high pressure causes temperatures to fall as it builds in and rise as it breaks down. Woodruff was aware that highs and lows “move almost invariably across the United States from west to east,” and further, that the movement of a low seemed to determine the movement of the high-pressure area following behind it, almost as if low pressure dragged high pressure along in its wake. “[O]ne storm begets its successor,” wrote Elias Loomis, a pioneer of American weather science whose Treatise on Meteorology Woodruff had read during his training course at Fort Myer. “The undulations thus excited in the atmosphere bear considerable analogy to the waves of the ocean agitated by a tempest, and which are propagated by mechanical laws long after the first exciting cause has ceased to act.”

  Woodruff concluded from researching his paper that the cold waves originating in “the vast regions of ice and snow near the arctic circle” almost always entered the United States through Montana, and from there took one of three tracks: due east “along the chain of great lakes and across New England”; southeast into Dakota, Nebraska, Iowa, Missouri, and so on across the entire country; or due south through Dakota Territory and all the way down to Texas, where the cold air sometimes veered northeast and spread up the Atlantic coast. The critical question for the forecaster was: What made a given cold wave take a particular track? Woodruff frankly admitted ignorance. “Even after a decided cold wave is observed in the extreme northwest,” he wrote in his paper, “we are not able to determine which one of the three paths it will take.” Greely conceded much the same thing, though rather more pompously, in his book American Weather: “As yet it has not been determined with absolute accuracy what conditions must obtain to induce the passage of cold waves” in one direction over another. “The question doubtless depends upon the relative relation of the centre of the anti-cyclone to that of some cyclone far distant.” Since they had no knowledge of fronts and their role in structuring storms and only the vaguest idea of how upper-air conditions influence what happens on the ground, forecasters of the day fell back on probabilities based on statistical analysis of existing data—and guesswork. Statistics told Woodruff that over half the cold waves entering the U.S. from Helena moved southeast, while only about a quarter plunged directly south down to Texas; and further that 71 percent of these Helena cold waves hit Bismarck in eight hours and 88 percent reached Omaha within a day. Interestingly, Woodruff also ascertained that nearly half of the cold waves in his sample were first detected at the 3 P.M. observations (2 P.M. Central time)—typically the warmest time of the day in winter—an insight that Greely mentioned (crediting Woodruff) in American Weather.

  It wasn’t much to go on in the face of the tremendous surge of energy spinning down at him from the north. A couple of formulas, a few charts of statistics, some rather murky mumbo-jumbo about the three possible paths. Even with a rooftop bristling with instruments and the all-important telegraph wires connecting him to the national grid, what Woodruff saw when he looked out from his office at the Saint Paul Chamber of Commerce building was more a mirror of his own mind than a window on reality.

  Woodruff and young Alexander McAdie broke for lunch as usual at 1 P.M. on January 11 and were back in the office at 2:30 P.M., Central time—half an hour after Lyons took the afternoon observations (the temperature in Saint Paul had risen 10 degrees since the morning readings to a comparatively balmy 15 below zero). One hundred and thirty-two other Signal Corps sergeants and privates were taking (or faking) observations at precisely the same time—3 P.M. in Washington, D.C.—but it would be two hours before the data arrived in Saint Paul from the Chicago Western Union office (to hasten distribution, a circuit was established through Chicago so that data from stations throughout the West could be transmitted simultaneously and then relayed to Saint Paul). And then it took McAdie another hour to translate the telegrams (weather messages were telegraphed in code to make them shorter—and thus cheaper to send—and to avoid numerical errors). Back at the Signal Office in Washington, they had the transcription and mapping process down to a science: as the telegrams came in on the wires from all over the country, a team of clerks read aloud the translations of the cipher while another clerical team recorded the new data, each clerk working on only one stream of data (temperature, air pressure, and so on). Meanwhile, the indications officers hovered behind the clerks and watched the pressure systems emerging on the maps, so that by the time all data were entered and all the isobars drawn, they were ready to issue their forecasts. Very likely McAdie and Woodruff worked in a similar fashion in Saint Paul, though necessarily more slowly since there were only two of them (or three when Private W. H. Ford was on duty).

  It was approaching 5 P.M. in Saint Paul before Woodruff got a clear picture of what had happened in the course of the day. The readings from Fort Assinniboine were startling. The pressure had fallen dramatic
ally since the 7 A.M. observations—from 27.06 to 26.76, a drop Woodruff had rarely seen in all his years in the West—while the temperature had risen 11 degrees, from 3 below to 8 above. Bismarck was also reporting a rapidly falling barometer and rising temperatures. Farther south in Huron, a stiff southeast wind had kicked up and the temperature had jumped 18 degrees, from 20 below at 7 A.M. to 2 below at 3 P.M.

  As Woodruff inked the isobars in red on the map, a distinct oval bowl of low pressure took shape around Medicine Hat in southern Alberta, just north of Fort Assinniboine: the first faint shadow of the coming storm.

  Woodruff and McAdie left the office at 5:45, shortly after tabulating the afternoon observations. The temperature was still rising in Saint Paul, odd for this time of day in winter, though with readings remaining in the double digits below zero, they hardly noticed. The men took four and half hours off for supper and a rest, and then returned to the Chamber of Commerce building at 10:15 P.M. to await the arrival of the nighttime observations from Chicago. Again there was the time lag due to the backlog at Western Union and then the tedious process of translation and transcription. Woodruff worked quickly on the charts—he and McAdie were eager to get home—and the highs and lows bloomed under his hand like faint red targets.

  He saw at once that the Alberta low from the afternoon chart had moved quickly to the southeast and was now centered over Fort Keogh, the eastern Montana army post where he had been stationed with his regiment when he was called up for signal duty. But still no outbreak of truly frigid air over the U.S. Fort Assinniboine reported 4 above at the 10 P.M. (Eastern time) observation with slightly rising barometer and northerly gales. Helena was 33 above, Bismarck 7 above, and the Huron station, staffed since 1881 by the conscientious Sergeant Samuel W. Glenn, was reporting a slightly falling barometer, stiff southeast winds, and a temperature rise of 5 degrees in the past seven hours, from 2 below to 3 above.

  The reading that stood out most starkly was the temperature at North Platte, in southwestern Nebraska: 22 degrees above zero at 10 P.M., a rise of 20 degrees since the 3 P.M. observations.

  It took Woodruff only a few minutes to complete the midnight indications. It was perfectly clear to him from the 10 P.M. observations that a deep low was in the process of dropping southeast over the country—the classic path. He knew that temperatures would rise in advance of the low and fall once it had passed. He knew that Helena held the key. Once temperature began to drop in Helena, they would be likely to drop in Bismarck eight hours later (71 percent of the time according his calculations) and in Saint Paul within twenty-four hours (73 percent of the time). But as of 10 P.M., Helena was still showing a rise of temperature—so there was as yet no cause for alarm. This rise in Helena was a bit puzzling, because according to Woodruff’s own formulation “a fall of temperature succeeds or follows an area of low barometer,” and the center of low pressure had already passed well to the south and east of Helena. Woodruff undoubtedly believed that this inconsistency would have been resolved if he had access to more timely data from a more extensive network of stations. As he had written in “Cold Waves and Their Progress,” the difficulty of forecasting “is increased by the fact that observations at our Signal Service stations are separated by intervals of eight hours.” Eight hours was an eternity meteorologically, especially in the wild and mercurial West.

  But there was one critical bit of data right there in front of him, if only he knew it. That 20-degree spike in temperature at North Platte was like an arsenal packed with explosives. The meaning of this reading was lost on Woodruff, as it would have been lost on Greely or Professor Abbe back in Washington. It was one more piece of data that didn’t fit what Greely termed the “principles of philosophy” that he insisted were “sufficient to explain the intricate and varied phenomena of the atmosphere.”

  By 11:45 P.M. on January 11, the indications for the following day were obvious to Woodruff. The Montana low would bring snow and rising temperatures to Dakota Territory during the day, followed by colder temperatures and northerly winds spreading over the region from west to east. The tight rings of isobars bunched together over southeastern Montana, northeastern Wyoming, and western Dakota indicated that pressure differences were particularly marked in this region—a clear sign of high winds. Woodruff thus predicted that sometime during the day the snow would drift heavily as stiff winds blew from the north in the wake of the low.

  No cold wave warning, however, was called for—there was no justification for it with temperatures of 33 above in Helena.

  When Woodruff and McAdie left the Saint Paul Signal Office a few minutes before midnight, E. J. Hobbs, the Signal Corps observer in Helena, was still awake and still on duty at the station. Word had reached him of severely cold weather bearing down from the north. Even though he was under no obligation to remain at his post, he had decided to stay up all night to monitor the situation. Strangely, temperatures continued to rise through the first hours of January 12. At 2:30 A.M., Hobbs recorded 38 above and the mercury hit 40.5 before dawn.

  Meanwhile 173 miles to the northeast, inside the long, sturdy brick structure that housed the Fort Assinniboine weather station, the Signal Corps observer on duty was observing something he had never seen before. The telegraph wires that connected the station’s receiver to the endless loops of wire strung over the plains were emitting strange flashes of light—“a constant play of light,” as the private noted in the station’s journal—and were so charged with electricity that they could not be handled. Even inside the station the air fairly crackled with electricity. And outside the weather was turning fiercer by the minute. The warm chinook wind that had blown out of the southwest all day was now howling out of the northwest at a velocity approaching 50 miles an hour.

  It was like a hurricane approaching over the empty plains of Montana in the dead of winter.

  CHAPTER FIVE

  Cold Front

  Of course, Lieutenant Woodruff and E. J. Hobbs in Helena and Sergeant Glenn in Huron knew what a cold front on the prairie felt like—the sudden shift in wind direction, the burst of rain or snow, the crystalline, head-clearing blast of cold air from the northwest. Woodruff even used the term “the front of the wave” in “Cold Waves and Their Progress” to describe how cold waves tend to track the paths of lows from northwest to southeast across the country. But it wasn’t until after World War I that a team of Norwegian meteorologists led by the physicist Vilhelm Bjerknes and his son Jacob zeroed in on the importance of cold and warm fronts in the structure of weather systems and devised a way of graphically representing their location and direction on weather maps. The insight of Vilhelm and Jacob Bjerknes nudged the fledgling science of meteorology one large step closer to maturity.

  The Bjerkneses borrowed the term “front” from the vocabulary of the war that had just decimated Europe and brought neutral Norway to the brink of mass starvation. In World War I, the fronts were the long, wavering lines where the two opposing armies met, dug in, fought, and advanced or retreated after terrific violence. The analogy, the Bjerkneses realized, fit weather exactly. Air masses at a front come together too rapidly to mix. Instead, at a cold front, an advancing mass of dense cold air shoves itself under warm air, forcing the warm air to rise rapidly along a steep incline and condense out its moisture: The speed and abruptness of the ascent typically results in short-lived bursts of heavy rain or snow, often accompanied by lightning. Warm fronts, in which warm air advances up and over cold air, progress more gradually and tend to bring lighter but steadier and longer-lasting precipitation to a wider area. Fronts are the seams in the atmosphere that extend from the ground to the tops of clouds—long, rippling, fragile seams that get ripped apart by storms.

  A colleague of the Bjerkneses in Bergen later came up with the idea of representing fronts on maps as lines of sawteeth—triangular barbs for cold fronts and soft semicircular pips for warm fronts. Today it’s hard to imagine the weather map without the warm and cold fronts snaking across it—but this
elegant bit of shorthand has only been around since the 1920s. There were no fronts on the maps Lieutenant Woodruff drew and distributed every morning to the eager citizens of Saint Paul.

  An evil genius could not have devised a more perfect battleground for clashing weather fronts than the prairies of North America. When conditions are right, which they frequently are, vigorous fronts unleash the worst weather in the world over this region—super-cell thunderstorms spawning tornadoes in late spring, huge globes of hail falling from anvil-topped cumulonimbus clouds in summer, blizzards in winter. On the prairie, cold fronts can come through so rapidly that standing water ices up in ridges, small animals literally freeze to their tracks, people whose clothing is wet find themselves encased in ice. When a strong cold front is accompanied by the blowing icedust of a blizzard, the punishment inflicted on human and beast is unimaginable.