Last night, like so many nights before, I drew a line on a sectional chart: Fargo, North Dakota, to the Coteau des Prairies, a range of hills just over the border in South Dakota. Seventy-three nautical miles on a heading of 190 degrees from home.
I’ve seen those hills a thousand times from the ground. Driving on Interstate 29, I’ve seen those hills rise on the western horizon, a pretty break on the flatland prairie, and I know just enough about geology to have wondered—why are those hills there? Today I have a partial answer, and I want to see them from the air.
While surfing the Internet one night, a picture showed up on the edge of my computer screen. It was a picture of my home, and it implied a story, so I spent some time reading. The Coteau des Prairies is just a pile of dirt pushed up into a moraine by a prehistoric ice sheet. That ice receded. When the next ice came—the famous Laurentide ice sheet—the Coteau des Prairies refused to move. It split the glacier and caused a deeper gouging of the land on each side. The hills are nothing spectacular, remarkable only because they are completely out of place, yet they even show up on the maps of Lewis and Clark as the Mountain on the Prairie.
What I really want to see today is invisible. From the left seat of a rented Cessna 172, heading south toward those rising hills, I want to see history. I want to see the force of the Laurentide ice sheet moving down the continent, and I want to see the hills split the ice. Imagine the slip of paper in a theatre program, “Tonight the part of the very large glacier will be played by a very small airplane.” You could call it a type of situational awareness.
There is a wonderful quote by writer Reg Saner. “Destination,” he says, “is mere pretext for the real business of going to meet it.” The reason we practice and refine the grace of our landings, the reason we calculate wind-correction angles and time between waypoints, is because the joy of holding a machine in the sky is profound. The more we know about the land we’re crossing, the deeper that joy becomes.
Examples abound. In summer, the approach to the International Peace Garden airport (S28) is calendar-art beautiful. Prairie farmland gives way to deep green forest near the Canadian border. Round hay bales and ponds dot the fields heading into Runway 28. It’s an easy landing, and the gardens are worth the trip.
There is a famous glitch in Microsoft Flight Simulator here. For whatever reason, in the computer world a giant chasm opens on the far end of the runway and you can fly nearly 30,000 feet down toward the center of the Earth. There is no such hole in real life, but there is something underground. You cannot see it from the air and you cannot see it on the ground, even if you’re looking for it hard. But one look at a gravity map shows this part of the state has some of the densest rock possible. Landing at the Peace Garden, it seems, is landing on the summit of an underground mountain.
It makes a difference in the way you understand where you are. The North Dakota Isostatic Gravity Anomaly Map isn’t hard to find. Just Google “North Dakota Gravity Map.” Better yet, Google whatever state you live in. Along the same lines, ever wonder why sectionals sometimes warn about extreme magnetic variations? There is something called an aeromagnetic anomaly map.
It all makes a difference. Long Island is a different place if you know the whole thing is a moraine pushed up by a glacier. The Grand Canyon is a different place if you know the Colorado River isn’t cutting down as much as the land is rising up, and the sight out your side of the airplane is more impressive if you’ve spent a moment with a map of the canyon wall and learned about the Great Unconformity. The Ozarks are different when you understand the hills used to be mountains that used to be an island in the midst of a Paleozoic Sea.
I remember learning ground reference—S-turns over a county road, turns around a point over some farmstead. Back then, the road and the farmstead didn’t really matter. They were arbitrary choices, references to use while I learned to muscle or finesse the airplane. Once I knew what I was doing, I wanted to know who travelled that road. I wanted to know who lived in that house.
One thing leads to another. Thirteen of the lower 48 states have impact craters left by meteorites. A map will show you the Manson Crater in Iowa, a hole large enough that scientists first thought this might be the site of the dinosaur-killer asteroid until the Yucatán site was discovered. You cannot see the Manson Crater—it was filled in long ago—but you’ll see it’s not very far from Madison County. The Bridges of Madison County can be seen from the air, however, and they are lovely.
We use our sectionals and approach charts. We use maps of winds aloft and maps of bad weather. We use maps of how our airplanes will behave (although we call them performance charts). We are experts with the maps that get us safely from takeoff to landing.
There are maps only a few of us ever see. FalconView, for example, is a version of the standard sectionals used by Department of Defense pilots. It’s not secret; it’s just not available to GA pilots. A government pilot once showed me an interesting bit of information on his map that was nowhere on mine.
My sectional does not say the buildings are an over-the-horizon radar site, but FalconView has a note-taking feature. The warning is nothing official. It’s just a bit of experience the pilots entered into their system. When I asked if there was any reason why I should avoid this site as well, the answer was probably not.
Back at home, I looked at an expired sectional. There was no reason, I thought, I couldn’t write my own notes. I got out my logbook and drew a line for every flight. I wrote “weekend sailboat races” next to Cormorant Lake, “fly fishing for brown trout” next to the Straight River, “Continental Divide” between the James and Sheyenne Rivers. And, yes, I wrote “Perimeter Area Radar: Avoid!” next to the buildings west of Cavalier.
If I have a story, a bit of personal history or local lore, I write it on an old sectional. If I have a desire for some future flight, that goes on the old map too. My friend Mike Paulson has promised to show me the inter-lake paddleboat trail in western Minnesota. I’ve promised myself the path of the Pony Express.
Sometimes the places we desire appear like Brigadoon overnight and disappear just as quickly. On the morning television weather report, we often see maps of last night’s rain or snowstorm, maps of storm totals and locations. Not so long ago, the map showed two and a half inches of rain from a Memorial Day storm just north of town.
I wanted some time in the air and a new place to visit. One inch of rain over one acre of land weighs more than 113 tons. This storm dropped 283 tons of water per acre: 67,885 gallons of water per acre. The next morning I was at 1,500 feet agl, following the rain paths, amazed.
The Coteau des Prairies rises in front of me, brown and green and beautiful in early fall daylight. I fly low, and from here I can easily imagine the advancing glaciers, the push and the resistance and then the breaking into two. The map in the Garmin G1000 is almost irrelevant today. Because of a different map I know I am flying over the bed of Pleistocene Lake Agassiz. Because of different maps I know the annual rainfall and population density. I know what types of rock rest under the soil and what crops were planted this year.
You could call it situational awareness. The Earth is simply more beautiful, and flying more rewarding, when you understand more deeply where you are. Destination, he said, is mere pretext for the real business of going to meet it.
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