WASHINGTON – When giving thanks this year, think of Lena Woebbecke. She and many others paid a terrible price for misreading the prairie sky on the afternoon of Jan. 12, 1888.

That day was unseasonably balmy, by prairie standards – some temperatures were in the 20s – and many children scampered to school without coats or gloves. Then, at about the time schools were adjourning, death, in the shape of a soot-gray cloud, appeared on the horizon of Dakota Territory and Nebraska.

In three minutes the temperature plunged 18 degrees. The next morning hundreds of people, more than 100 of them children, were dead beneath the snow drifts. David Laskin, a Seattle writer, reconstructs this tragedy in a terrifying but beautifully written new book, “The Children’s Blizzard.”

It picks up the many threads of the story in Norway, Ukraine, Germany, Vermont and other tributaries to the river of immigration set in motion partly by the 1862 Homestead Act. In return for an $18 filing fee and five years farming, the act conferred ownership of 160 acres. By the tens of thousands the homesteaders came, to live in sod houses, heated by burning buffalo chips and twisted hay.

Of immigrants, the saying was that the cowards stayed home and the weak died on the way. One in 10 crossing the Atlantic in steerage did die. But Laskin says “the mystique of the Dakotas” was such that the territory’s population nearly quadrupled in the 1880s. Those who made it, with a trunk or two and the clothes on their backs, reached towns that were perishable scratches on the prairie. They got land, freedom and hope.

And prairie fires. And grasshoppers, 100 billion at a time in roaring clouds a mile high and 100 miles across. And iron weather in which children, disoriented by horizontal streams of snow as hard as rock and fine as dust, froze to death groping their way home from a school 150 yards away.

Lena was 5 in 1882 when her father, a German immigrant, died of smallpox. Her mother remarried twice, having 11 children, eight of whom survived. In August 1887 Lena, her marriage prospects diminished by her smallpox scars, was sent to live with the Woebbeckes and their three children in a two-room house. It was half a mile from the school where she was, five months later, when a cataclysmic cold front came dropping southeast out of Canada at 45 miles per hour.

“To those standing outside,” Laskin writes, “it looked like the northwest corner of the sky was suddenly filling and bulging and ripping open.” In four and a half hours the temperature at Helena, Mont., fell 50 degrees. The prairie air tingled with the electricity of a horizontal thunderstorm. All over the region, school teachers, many of them not much older or more educated than their pupils, had to make life and death decisions about how to get the children home.

“The fear came first,” Laskin writes, “but the cold followed so hard on its heels that it was impossible to tell the difference.” In minutes nostrils were clogged by ice. Eyelids were torn by repeated attempts to prevent them from freezing shut. Unable to see their hands in front of their faces, people died wandering a few yards from their houses, unable to hear, over the keening wind, pots being pounded a few yards away to tell them the way to safety.

“For years afterward,” writes Laskin, “at gatherings of any size in Dakota or Nebraska, there would always be people walking on wooden legs or holding fingerless hands behind their backs or hiding missing ears under hats – victims of the blizzard.” Lena learned to walk on a wooden foot. In 1901, at 24, she married. At 25 she died, perhaps in childbirth, or perhaps of a complication from the amputation necessitated by frostbite.

“Lena was laid to rest in her wedding dress in the graveyard of the Immanuel Lutheran Church near the country crossroads called Ruby. If there ever was a town called Ruby, it has disappeared, as has the Immanuel Lutheran Church. The church cemetery remains – a fenced patch of rough grass studded with headstones between two farmhouses not far from the interstate. A tiny island of the dead in the sea of Nebraska agriculture.”

This Thanksgiving, when you have rendered yourself torpid by ingesting an excess of America’s agricultural bounties, summon thoughts of thanks for the likes of Lena, those whose hard lives paved the stony road to America’s current comforts.

George Will is a Washington Post columnist. Contact him by writing to georgewill@washpost.com.