Driving the Loess Hills Ridge

Past the levees, on almost any road west of Onawa, the land does something it has no business doing in Iowa. The flat ground tilts. The section-line grid wavers. The pavement bends into a switchback, and then the car is climbing a real hill, with a summit and a view, and behind it the Missouri Valley spreads out flat as a tabletop — a mile of cottonwoods, corn, and the brown river coiling south.

These are the Loess Hills, and the first glimpse is hard to trust. They are made of dust. Loess, from an old Swiss-German word for loose, is windblown silt, and along this reach of the Missouri it lies two hundred feet deep in places. That is not a metaphor. The hills are dunes that stood so long they grew grass, grew oaks, grew a whole stubborn country of their own.

The range runs a long two hundred miles up and down the east side of the river, from the country below Sioux City to the bluff lands above St. Joseph, Missouri. Nothing here would count as a mountain anywhere else on earth. But in a state where a rise of fifty feet is called a hill, these ridges stand two hundred feet and more above the bottoms and break every rule of the surrounding prairie. Iowa is supposed to be flat and fenced in squares. The Loess Hills are curved, steep, gullied, and unplowable.

The roads that go in are the old township lines that refused to stay straight. The Loess Hills Scenic Byway strings together the best of them, linking the river towns to the ridge towns — Onawa, Turin, Pisgah, Mondamin — by way of the high country where the grain elevators stand against the sky and the wind never entirely stops.

The Wind That Piled Them

Dust is not supposed to hold a shape. But loess is the one soil that does, and it owes the trick to the last ice age. The glaciers ground the northern rock to a fine gray flour, and the meltwater spread it across the Missouri Valley in braided flats. The wind did the rest. For thousands of years it lifted the finest silt off the floodplain and dropped it against the eastern bluffs, building the ridges the way a dune is built — grain by grain, season by season.

The river never cooperated with borders. The Missouri has wandered across that valley for a long time, cutting into the hills and then swinging away, leaving them high and dry. Lewis and Clark came up the river in the summer of 1804 and made their way past these pale banks. The hills were already ancient then, and the people who lived among them were older still.

In 1955, a road crew cutting a hillside near the Monona County town of Turin uncovered a human skeleton buried in the loess. Radiocarbon dating later placed the burial about three thousand years back. He is known now as the Turin Man, and he had been lying in the hills through all the written history of the continent before the graders found him. The pale soil that made the hills also kept him, sealed in dust as dry and fine as flour.

The soil keeps other accounts as well. When loess dries, it stands almost vertical; roadcuts show sheer faces of pale tan dirt that look poured rather than deposited. When it wets, it fails. The slopes crawl, the pavement cracks, and every spring the county crews patch the same creeping slumps on the same bends. In the summer of 2011 the river lost its temper and sat on the valley for weeks; the town of Hamburg, at Iowa's southwest corner, went under. From the ridgelines the reason showed plainly: the first farmers built on the high ground, and the hills stayed wild on the slopes where the plow could not hold.

The Grass That Was Always There

Because the hills were too steep to plow, they kept what the rest of Iowa lost. The prairie on these ridges is not restored; it is original. Little bluestem and big bluestem bend in the same wind they have bent in for centuries. Indian grass stands taller than a man in the draws. And mixed in among the grasses are the oddities that always lived here — yucca spiking up in June, prickly pear cactus hugging the dry south slopes, leadplant and purple prairie clover holding the ground between.

The two faces of a ridge do different work. The north slopes catch the shade and the damp and grow bur oak and red cedar into knotty, close-built groves. The south slopes take the full sun and the wind and stay short-grass prairie — hot in summer, gray and gold in winter. It is a country of edges, and the edges are what hold the life.

The sharpness kept the towns small. Turin, Pisgah, and Mondamin sit in the valleys with their elevators half full and their Main Streets one block long. Logan keeps the county courthouse on the crest. The man who runs the feed store in one of these towns will tell anyone who asks that the hills get in the blood; it is visible in the ones who stay.

The wild country returns the favor. Grasshopper sparrows sing from the fence lines in summer. Northern harriers row low over the grass in winter, white rumps flashing. Come October, the ridgeline becomes a migration road: broad-winged hawks and Swainson's hawks ride the thermals along the escarpment, and the watchers at Hitchcock Nature Center, on a high point above the river, keep the count through the afternoon. The hills act on migrating birds the way a headland acts on sailors — a line of lift, a landmark, a place to turn.

The state has set aside pieces of it. Waubonsie State Park holds the southern bluffs, where the trail drops through oak shade to a bench of open prairie. Preparation Canyon lies deeper north, its slopes so steep the park feels hollowed out. The Loess Hills State Forest combs the ridgelines near Pisgah with old haul roads gone back to grass. None of them is crowded. On a June morning the loudest thing in the park is the wind.

Roads That Follow the Sky

The best way to see the hills is from the road, moving. The byway bends where the ridges bend, climbing out of Sioux City in the north as a two-lane the truckers never learned, running the high spine through the state forest, and dropping south toward the river towns again. US-30 comes off the bridge at Blair, Nebraska, and climbs the ridge in long, grumbling pulls, running the crest past Logan before it descends to Missouri Valley. Down in the valley, I-29 carries the impatient traffic north and south and sees none of it. The interstate is the way through. The ridge road is the way in.

The hills do something strange at the right hour. In November, when the leaves are down and the river fog lies thick in the bottoms, the ridges rise out of the white like islands. The sun comes up over flat Iowa to the east and strikes the pale west faces, and for a few minutes the whole range goes apricot, then gold, then ordinary dirt again.

Summer afternoons come violent. Heat piles in the valleys, storms build over the river by midafternoon, the sky goes green before the hail, and lightning walks down the ridgelines. Winters are worse motoring and best for looking: no leaves, thin light, the loess pale as bone in the roadcuts, bald eagles down from the north sitting in the cottonwoods along the river. When ice takes the ridgeline roads, the county closes them without ceremony, and the hills go back to being empty, wind-scoured, and entirely themselves.

Spring comes up the ridges in a wave. The grass greens first on the south slopes, then the crests, then the north faces; the wild plum thickets go white in the draws; and the river below runs high and brown from the plains to the west. From the high bluffs at Waubonsie, the Missouri bends south through Nebraska and Kansas, a long muddy artery feeding a country that once, on these very bluffs, stood two hundred feet deep in dust.

The hills have held since the last ice age, and they are still being made. Each year the wind takes a little more of the field tops and adds it to the eastern country; each spring the rain pulls a little more of the west faces down toward the river. Standing on a ridge at dusk, with the Missouri glinting far below and a farm light coming on in a draw, it is easy to feel the land still in motion, still being sorted by the long western wind. The road runs along the crest. The dust settles behind it.

Photos: Chris Light (CC BY-SA 4.0)