Blazing Ice (22 page)

This year, Judy flew down to McMurdo on the same plane with me. It was early October. Right behind us came U.S. Air Force C-17s bearing our improved sled parts. Our hopes for success turned on these parts and the fifth tractor.

Two days away now from the farthest south of our second year at RIS-1, lumbering toward that blue-on-white horizon, recollections of time wasted invaded my cab. Outside, on our compacted snow road, everything—
everything
—we did to improve our mobility after our disappointing second year worked. But beyond that wooden post at RIS-1 lay virgin snow and no trail. Somewhere ahead lurked a crevasse field we didn't know much about.

“Alger!” I radioed the radar team ranging in front of the heavy fleet.

“Go ahead,
Fritzy
,” Alger drawled with accents of Michigan.

“When you guys get to our campsite at the end of the day, sweep a broad circle around the camp flag, a couple hundred foot radius. We're going to do that every day from now on. We'll call that our camp circle. If you don't find any crevasses on that circle, then we'll pull into it and make camp. Do you understand?”

“You betcha,
Fritzy
.”

Route planning consumed me in the off-season. The land could kill us. Historical works from the earliest explorers, reports from 1950s science expeditions, opinions from modern glaciologists, maps both modern and old, and all the latest satellite information I could get my hands on went into route planning. Two-week excursions into matrixed analyses that nobody read wasted time that would've been far better spent making sure my crew survived.

Terrain assessments often pointed to regions of crevasse
probability
rather than certainty. I'd briefed the crew on suspected crevasses ahead. But with our mixed backgrounds, probability meant different things. The ultimate crevasse hazard, however, meant the same to each of us. Alger's PistenBully tracks would say, “stay inside this circle,” a safe perimeter everybody could grasp at a glance.

“John, I could smell the fear on you guys this morning when you brought up the snow swamp. Last year must have been just horrible.” Judy caught me outside, attending to
Fritzy
on the morning of November 30. We were breaking camp at RIS-1, starting our tractors and rigging for travel.

“It was. You understand we're going onto virgin snow? We travel close from now on. Watch that train in front of you. If a sled's breaking, we need to catch it before the whole thing collapses.”

“I got that loud and clear,” Judy acknowledged, moving off to #283.

We'd arrived at RIS-1 four days earlier, fully one month ahead of our arrival the year before. Ahead, ice-covered peaks of the Transantarctic Range broke up our formerly smooth horizon. While we waited for the Twin Otter, we spent a breezy day under clear blue skies tending to camp chores and playing.

Brad, Mike, and Stretch flew a colorful, two-handed parasail kite my wife and kids had given us. Brad, flying the kite, stepped onto one of our slick recovery skis. Soon that kite pulled three grown, giggling men, one after the other, around the camp circle, riding the three-foot-by-ten-foot plastic sheet like a surfboard.

John Penney launched his remote-controlled model airplane and flew it overhead. He'd attached a lightweight digital camera under its wing. From that day on, when weather allowed, we enjoyed seeing oblique aerial photos of our camp on his laptop.

The Twin Otter brought Jim Lever and our replacement mountaineer Susan Detweiler. She was a svelte, muscular woman wearing long brunette tresses. Her eyes, her whole bearing, said, “I'm here to help.” During the next day in camp, the newcomers learned the ropes.

John Penney captained the radar team on a training mission to lay out the next several miles of trail. All three team members had to coordinate their work, and that required practice. Jim and Susan were new to the business. Jim operated the PistenBully, navigating the course I gave him. Susan rode shotgun with the radar, looking for hidden crevasses. John ran behind them on a snowmobile, pulling a wooden Nansen sled loaded with green flags. At day's end, John pronounced his team good to go. Green flags, planted straight and on course every quarter mile, marked the safe path.

On the morning Judy smelled our fear, we launched the heavy fleet down John Penney's nine miles of newly flagged trail leading south. We didn't find crevasses that day. Within two hours, a fierce head wind blowing horizontal snow found us. We hunkered down at the end of John Penney's flag line with nine miles made good. The Leverett Glacier sat 230 miles away.

The blizzard stayed with us through the next morning. Drift snow buried our fleet. We dug out, fired up our tractors, and pulled our camp into the wind. Then we hunkered down again, expecting sooner or later the storm would blow itself out. But it didn't. We logged one hundred yards that day.

“
Fritzy
,” my radio squawked. Susan's voice.

“Go ahead, Warrior Princess.”

Susan was new to heavy equipment. When we were still at McMurdo, she and Mike Roberts led us in a training session at a “practice crevasse” near town. I took Susan out there in
Fritzy
, our shared cab time an opportunity to review my expectations for her on the trail. Since we'd taken a shortcut, we arrived at the practice grounds ahead of the others. I introduced her to
Fritzy
and its crane. She unshyly took the controls. After the others joined us, she and Mike took over. We spent the rest of the afternoon working with knots and webs of rope, raising volunteer bodies out of the makeshift snow trench. Susan won our unanimous thumbs up.

“
Fritzy
,” she radioed now. “We have a strange image on our screen. You should look at it.”

“Copy that. All halt,” I radioed the moving fleet. We stopped just over a hundred miles south of RIS-1. The radar team had been flagging new trail a mile ahead of us. Susan brought back the image. When the red PistenBully pulled up opposite my yellow tractor, third in line, I dismounted to see what she'd spotted.

“Good catch,” I complimented her when she showed me the screen. In a field full of crevasses, the image was so small it would've been insignificant. But after miles of boring flat stratigraphy beneath us, Susan saw something different: a vague discontinuity in the layers twelve meters below the surface. That was deep.

“Susan has found something,” I radioed to the others. “It's not a crevasse, but it is some kind of disturbance. And it's well below us. We're going to proceed, but be ready to stop again.” Then off radio, and looking to Susan and Jim in the PistenBully: “Let me know immediately if you see any more of that stuff.”

Two miles later, Susan radioed back, “
Fritzy
, we have more, and they are shallower.”

“Make the camp circle!” I closed my eyes, sucking in a deep breath through clenched teeth. The day was December 4, 2004.

During the off-season, George Blaisdell had reviewed RADARSAT satellite imagery of the area. He inferred that a crevasse field might be lying around here. The imagery didn't show crevasses, but it did show flow patterns where mountain glaciers merged with the Ross Ice Shelf. Icy turbulence at those confluences could make crevasses.

Now we camped fifteen miles short of our next turning point. Blaisdell had hoped RIS-2 might be located in crevasse-free ground south of the suspected field. And I nursed a hope of avoiding the field all together by steering right to his point.

The next day, with the mountains tantalizingly close, we launched the ten-thousand pound PistenBully toward RIS-2. Jim Lever's earlier studies in the Shear Zone had shown us what bridge thicknesses would support that light machine, and we had the skills to judge those in advance while we moved ahead and to stop if we had to. But none of that relieved the creeps we felt for crossing over a bridged crevasse.

I rode in the back of the PistenBully, looking over Susan's shoulder at the radar images. In those fifteen miles, we crossed over more than a hundred bridged, hidden crevasses. These were serious, not just deeply buried sign. RIS-2 sat right in the middle of them. I'd not risk running the heavy fleet over that ground without investigating each one. And there was not enough dynamite on the continent to blow them all. We'd have to find a way around.

“We're going to be here for a while,” I announced back in camp. “Prepare for a siege.”

That evening, I placed a note in a bottle and cast it into the e-mail ether. It might find Dave Bresnahan. He sat in the big chair in McMurdo then. My message read:

We're camped fifteen miles short of RIS-2, on course RIS-1 to RIS-2. Between this place and RIS-2 we have encountered many crevasses. RIS-2 lies squarely in crevasse territory. We are seeking a route solution around whatever is in front of us with means we have at hand. Can you enlist George Blaisdell to review satellite imagery for the same purpose?

For the next six days we camped on the brink of this crevasse field. The first three of those days we explored ever more south and east, toward the base of the Leverett. I ran the PistenBully. Susan read the radar. Stretch and Judy followed us on snowmobiles, flagging our track. Our prospecting loops covered ten miles by fifteen miles. Everywhere we looked, we mapped hundreds more hidden crevasses under that featureless snow surface. We found no sign of a passage through them.

Those same three days, Russ and John Penney stayed in camp anchoring our communications and attending to maintenance. Jim Lever and Brad Johnson stayed back, too, running mobility studies on safe ground. After three days, those four grew dangerously bored waiting for a new direction. I'd been stalling. Now I needed work for all of us to do together.

The next morning, we departed camp toward RIS-2 with the PistenBully pulling our hot water drill on a makeshift sled. Two in the PistenBully, two riding the drill, and two each on snowmobiles brought all eight of us into the crevasse field.

We drilled bridges to gauge their thickness and span. We measured snow strengths with the rammsonde penetrometer that we carried with us this year. We mapped the courses of the hidden crevasses with our radar. And we built complete pictures of several crevasses, combining their radar images with the drilling profiles and bridge strengths. We learned a great deal about the crevasses in that particular area, but because of the sheer number of them our efforts to evaluate each crossing were futile. Over six days we found no joy on the ground.

But my note-in-a-bottle had found its mark. Dave had caught George in transit from the United States to New Zealand. George was headed for Mc-Murdo where he'd take his first turn in the big chair.

When George learned of our trouble, he contacted two NSF grantee glaciologists. Both were attached to NASA, but both were familiar with our region of the Ice Shelf. They introduced George to ASTER satellite imagery, newer stuff than RADARSAT offered. ASTER—Advanced Spaceborne Thermal Emission and Reflection Radiometer—was a joint U.S.-Japanese earth-observing satellite launched in 1999. ASTER used both thermal and visible light spectrums, rather than microwave radar. And it offered higher resolution imagery. ASTER showed elongated, narrow shadows in our region.

By the time George arrived in McMurdo, he had ASTER imagery in hand. In a great stroke, he arranged collaboration with McMurdo's geographic information systems (GIS) analyst, Jessica Walker, who had also been a vital player in my preseason route planning. She knew our proposed route and the nuances associated with it. She magically called up all manner of digital information on her computer and transposed it onto our maps. ASTER gave her exactly the type of information she could use.

George and Jessica became our “eyes in the sky.” Using our Iridium link, I sent them ground truth from our own ground-based radar to calibrate their interpretations of ASTER's images.

“What I'm seeing here appears to be shadows cast by sagging crevasse bridges. There are a lot of them surrounding RIS-2,” George explained over the Iridium phone. “Do you see sagging bridges on the ground where you are?”

We already knew there were a lot of crevasses around RIS-2, but we didn't see sagging bridges at ground level. And I was pretty sure we saw crevasses with our radar where ASTER didn't see any.

“Keep the ground truth coming in. The glaciologists think there is a crevasse-free gap in the field, and a clear path to the Leverett south of that. I'll keep studying the images.” George had just arrived in McMurdo. He had a lot of business on his plate besides ours.

Meanwhile, we'd exhausted our strategies for a route solution on the ground and readied to leave the area. Our inability to advance frustrated us. I planned to retreat north a few miles, and then run southeast toward the Leverett, staying well north of the crevasse field. We might get sixty miles in one pitch, and we could shuttle the camp along that baseline. From any point on the baseline we could safely launch the PistenBully southward, seeking to penetrate the field. Making sixty miles by itself would be a welcome change.

“We really haven't looked west yet,” Russ observed.

West took us away from the Leverett. But there was no good reason
not
to look west while we were here.

Blinding white-yellow sunlight flashed through the PistenBully's windshield. The antenna boom lurched skyward. We buckled, slipping backward through the broken lid of a crevasse. I gunned the engine as we desperately clawed our way up to flat ground. For long minutes, Susan and I stared ahead at the right-wise horizon. Neither of us said a word.

The westerly course took us out of sight of camp, out of VHF radio range, and down into a rolling ice valley. Brown, tan, and red strata in the mountains ahead displayed an unreal clarity through partings in their icy mantles. The day was brilliant and calm.

We'd passed over deep crevasse sign in the first two miles. At a prearranged turning point, we turned south and found sign more frequently. All looked like everything else we'd seen in the preceding days. I looked over to Susan. “Shall we see what we have here?” She looked back through wide-open eyes, like mine.