The Lava Fields of Craters of the Moon

The road southwest out of Arco carries three highway numbers at once, and it runs arrow-straight across the Snake River Plain. The Lost River Range stands off to the north, a wall of peaks that holds Idaho's highest summit and keeps its snow long into the spring. For miles there is nothing but sagebrush, gravel, and the pale curve of asphalt, and the eye learns to measure distance in fence posts.

Then the ground begins to darken. It is gradual at first, a sootiness in the gravel, and then the black spreads and thickens until whole fields stand knee-deep in broken basalt. Cinder cones rise out of the flatness like ships at anchor. By the time the park entrance appears, the driver has left the plain behind and entered the country the plain used to be before the earth opened under it.

The shape of the plain

Geologists read the Snake River Plain as a trail of scars. The crust of the West moved southwest over a fixed plume of heat that now burns beneath Yellowstone, and the plume punched through the crust again and again, dragging a line of volcanic fields behind it from the Oregon country to the Wyoming line. The plain is what that violence settled into: a broad, smooth, open stretch of southern Idaho that looks from a distance like the easiest land in America.

It is not easy land. The wind is the first thing anyone learns here. It comes off the ranges and crosses miles of open ground without a stop, carrying the dry smell of sage and dust. Rain is scarce, and the irrigated fields are green only where the pivot sprinklers have reached. The towns — Arco, Carey, Rupert — sit far apart, and the long highways between them carry the trucks and nothing else but weather. The plain looks smooth from a distance. Up close it is cut with dry washes, stitched with fence lines, and strewn with basalt where the thin topsoil has given up. The Snake River, which gave the plain its name, crosses it on its way to the Pacific, and along the river are the only trees for miles.

The lava fields are the plain's other interruption. The great one is Craters of the Moon, a dark country the sagebrush has never quite covered. It shows itself from a distance as a low black smudge on the horizon, and a traveler can watch it grow for the better part of an hour before reaching it. Nothing else on the plain behaves that way. Everything else just sits where it has always sat and gets worn smooth.

The country the earth made

The lava at Craters of the Moon looks as though it stopped moving last week. It is blue-black where it has been broken, glassy in patches, pocked like old bread in others, and it keeps every sharp edge it acquired the day it cooled. Two thousand years is nothing in the life of rock, and this basalt has not had time to rot or to round off against the wind. The Great Rift runs beneath the field, a crack in the earth that continues for scores of miles across the plain, and along its line the ground opened again and again, building cinder cones and spatter cones and long rough flows of lava. The last eruption ended only a couple of thousand years ago.

The loop road leaves the visitor center and winds for seven miles among the cones. It is a road built slowly, with the rock winning most of the arguments; it climbs, dips, and swings around the bases of hills that a stranger might take for ordinary mountains. Inferno Cone rises beside the road on one side, and the Watchman stands off on the other. The trail up Inferno Cone is short and nearly vertical, and the cinder rolls underfoot as though the hill is still deciding how it feels about being climbed. From the top, the whole field opens out — black rumpled cloth stitched with a thousand low craters, with the white ranges of central Idaho floating at the edges. The wind up there has no manners at all.

Nothing in this country is soft. The cinders are loose and ankle-turning, and every step announces itself like a footstep on a floor of broken plates. The spatter cones sit low and lumpy beside the road, built of pasty blobs that fused where they landed, and a person can walk right up and touch the exact moment the earth was in a bad temper. Farther along, the loop crosses blocks as big as cars, a field the rangers call the Devils Orchard, where the rock jumbles so thick that the sagebrush has to scramble up piles of rubble to get daylight. It is a garden, if the gardener hated everything.

There are caves too — lava tubes left behind when the molten rock drained away. Indian Tunnel lies open along its top, the ceiling fallen in at long intervals, so a walk through it is a rhythm of bright shafts and long cold dark. The air in the tube does not move, and it stays cool even in July. The rubble floor gives no quarter, and the quiet is such that a footstep rings out like a struck glass. Some of the other tubes are gated and closed by regulation while the bats use them, and the rangers hand out permits for the caves that stay open. The cold down there is a different order of cold, the kind that built up when the country was young and has not bothered to leave.

Life in the cracks

The lava field is a map of scarcity, and life on it arranges itself in islands. Wherever wind and rain have gathered dust into a pocket deep enough to hold moisture, the desert starts over again: big sagebrush, rabbitbrush, the low gray shrubs of the plain outside. In a wet spring, flowers come up between the cinders, so small and so low that a person has to kneel to find them. Limber pines, stunted and wind-shorn, stand where a root can get a grip, some of them older than the name of the place.

The animals use the field the same way. Marmots sun themselves on the warm rock and whistle; the cracks and tubes give shelter from every weather the plain can throw. Under the islands of soil, pocket gophers work the ground, turning earth out through their burrows into mounds that may be the only new soil in a mile of black rock. For a seed blown in on the wind, a gopher mound is the whole estate. The chain runs from the gopher to the grass to the hawk, and the hawk keeps an eye on the whole field.

Winter is the season that suits the place. Snow piles into the cracks and stays, tracing the black rock with white lines. The loop road shuts to cars, and the field goes quiet except for skis and ravens. The lava is so young that it does not hold soil, and the snowmelt disappears straight into the rubble instead of running off; the dry washes of the plain run only after rain. Spring comes late at nearly six thousand feet, and it comes slowly — first the gray of sagebrush, then the green, then the small bright colors no one is expecting.

A name borrowed from the moon

The people who crossed this country before it had an English name knew the field well enough to leave traces — old routes that thread across the rift between one stretch of open ground and the next, worn into the cinders by generations of use. The land was not empty, and it was not unknown. It simply had not yet been named for anything so far away.

In the early 1920s an Idaho outdoorsman named Robert Limbert came through with a camera and carried away a name. Craters of the Moon, he called it, and the name took. The monument was declared in 1924, and Limbert's photographs made the case that the place was too strange to be left unmarked.

Decades later, the men who were bound for the real moon came here to practice. Apollo crews walked the cinders with geologists, learning to read a world made of nothing but rock and distance. The field was the nearest thing on earth to the surface they were bound for — not a perfect match, but close enough to teach them how to look, and how long to look, and what a rock says by the way it lies. The moon they reached has no wind and no sage. But the habit of attention they practiced here served them well out there.

Night is the true time for all of this. The field empties, the air cools, and the sky opens up until the Milky Way runs straight overhead. The ground below is nearly as black as the sky, so the world becomes one dark field full of lights — the stars above, and below nothing but the pale line of the road and the warmth of the day coming back up out of the basalt. It is a landscape that refuses the easy comparison. It simply sits there, black and young, older than any name but newer than almost every other rock in the country, waiting for two thousand years to become a long time.

Photos: Matthew Dillon, James St. John (CC BY 2.0)