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.
Susan roped us up, tying off to the PistenBully. We looked gingerly into the blackness of the hole behind us. A four-foot-wide crevasse hid beneath a strangely thin, broken bridge.
I called back to camp on the Iridium phone. “Judy, we are turning back for your position. When we get there, we’ll break camp and move north a bit. Pass the word. We’ll head your way just as soon as we figure how to get back across this crevasse.”
“Copy all,” Judy acknowledged. But she understood what had happened, adding, “Be careful.”
Still roped up, Susan and I probed the snow with long, thin poles to locate fissure’s hidden course. We’d crossed it squarely. A hundred feet to the west it narrowed to two feet. We re-crossed it there.
Once on the camp-side of the crevasse, we turned the radar back onto it as far as the antenna would reach. It showed us an image unlike any we’d seen. It lacked clarity. There was no inverted parabolic shape, no sign of a bridge or sagging surface layers. Yet there was an image, and we’d missed calling stop.
Outside the idling PistenBully, Susan and I stretched in what warmth the summer sun offered. We wasted no thoughts on recriminations. We read each other’s eyes, gauged each other’s breathing. The picturesque horizon spread south of us. When smiles eventually appeared, our adrenaline had run its course and we returned to camp.
“We’re not going that way either,” I told the others, gathered in the galley. “We’ll talk about what happened tomorrow morning. For now, let’s move out. We’re going to try something else.” And my message to McMurdo that evening said simply, “There is nothing more for us to do in this place.”
We retreated ten miles from that first faint sign Susan spotted on entering the territory. Ten miles seemed a safe enough margin, and we named the new camp FORK. Behind us, more than two hundred flags marked abandoned trails through the maze of crevasses. Among them was a wooden post, planted at RIS-2, bearing the name “McCabe.” James McCabe from Texas had toiled with us the year before. He was unable to rejoin us this year, and we missed him.
“CHRISTMAS CONTEST—$1,000,000 prize for the best drag design for our purposes.”
The announcement appeared on the white board in our galley the next morning at FORK. A “drag” is a trail-grooming device, dragged behind a tractor or a sled. Our makeshift drags bogged us down. The million dollar prize for a better design got everybody’s attention.
“For us to design one, you got to tell us what the purpose of the drag is,” Russ complained.
“Yeah … but the prize is as much for what you think our purposes are, as for the design itself.” I left it at that. Russ grumbled. But now we were thinking about something besides crevasses. And the promise of movement today lifted our spirits.
We reached the end of the baseline two days and sixty-four miles later. Since we were already there, I decided to explore the ground south of us. Our whole fleet turned directly toward the base of the Leverett Glacier, a coordinate location for us, since it was still too far off to see. Within five miles we halted at our first crevasse. Prospects of another siege brought us down again.
We explored much as we had near RIS-2. But unlike there, where ten miles revealed a hundred hidden crevasses, here we found twice that number. To test how efficiently we could evaluate crevasse bridges in a single day, we targeted eight, but completed only six. A southern passage here was as futile as ever.
“George, are you seeing any crevasses immediately south of our position?” I asked our McMurdo eyes.
“I see clusters of crevasses perhaps twenty and thirty miles south of your position. But I see none on the ASTER imagery where you are now.” George shuffled un-gridded photo mosaics, a work in progress, around his desktop trying to answer my questions.
“Copy that. We’re going to prospect here a little longer,” I signed off.
Outside the living module near Fritzy, a droop-shouldered Russ Magsig duck-footed his way over the snow toward me. His head hung down, swinging side to side. He wore a plaintive look. “We can always go back to the Skelton and try it from there.”
The Skelton Glacier, much closer to McMurdo, was the pass Sir Edmund Hillary chose for his historic tractor traverse to Pole in 1957–1958. It was way over there and certainly not for us this year. And, it was riddled with crevasses. Hillary had found plenty. Evans’s crew in 1995 went there and found exactly what Hillary found. The Skelton made a distant second choice to the Leverett. The only reason the Skelton had made the list of candidate passes was that Hillary had done it. But we sought a safe, repeatable route, not a risky one. And now I saw depression creeping into camp.
At our morning briefing the next day, I laid out our situation: “We are here. Our job for this season is to find a way to the base of the Leverett Glacier. We are safe, we have plenty of food, we are warm, and we have fuel. We are not going to leave this region until we’ve exhausted all our efforts, or spent half our fuel, to get to the Leverett base. Consider going back to McMurdo before we’ve done all we could. Do you really want to go back to McMurdo at all? We’re in a mighty fine place, right here in the middle of nowhere. And we have an interesting problem to solve. Maybe we’ll find a solution.”
Grim faces nodded in silent assent. Putting it my way, not one of us wanted to go back to McMurdo.
Our eyes sent in a detailed description of a route segment on the far side of the crevasse field. As far as ASTER could determine, it was crevasse-free. And it was within reach of the PistenBully so long as we staged extra fuel forward. If we could cross the crevasses in front of us, we could test ASTER�
��s findings. But should anything happen to the radar team, none of the heavy tractors could safely follow us to the rescue.
We made a plan for exploring a triangular loop that crossed the field. The opposite leg of that triangle was the ASTER segment. It might take two or three days to carry out the plan, though my daily reports simply said we were prospecting.
The first day, Judy accompanied Susan, Jim, and me in the PistenBully. Judy ran the radar under Susan’s watchful eye. Susan kept tally of the crevasses we crossed. First, we retraced our path toward the base of the Leverett. We’d already identified 214 crevasses on those ten miles. At the end of the line we staged a drum of fuel and called the place DRUM. From DRUM, we turned a westerly course toward one end of that distant, ASTER route segment. Judy called sixty hidden crevasses along the next five miles before we turned back for DRUM, and then camp. As we got out of the PistenBully, she remarked, “This is just like hunting rattlesnakes!”
For the whole prospecting loop, we’d take our two snowmobiles with the PistenBully. The snowmobiles gave us a way to return to camp in an emergency. We didn’t plan to run them. But we’d tow them with enough fuel onboard to cover the distance.
Should the PistenBully fall into a crevasse with the snowmobiles towed closely behind, they’d follow it in. So we rigged a two-hundred-foot-long line of heavy, knotted tow-rope. It hooked to the PistenBully on one end and to a pair of slick plastic sleds on the other. The sleds, lashed side by side, bore the two snowmobiles. A webbing of heavy cargo chain formed the hitch to the sleds. When the PistenBully pulled the sleds, the tow rope and the chains rode taut. But, if the PistenBully stopped, the chains fell slack.
In the safety of our camp circle, we ran the PistenBully at full speed then stopped abruptly. The snowmobile sleds overran the chains as we’d hoped. The chain-brake dragged the whole package, with one passenger on board, to a stop in twenty feet. That satisfied us.
On the clear morning of December 19, we loaded mechanic’s tools, emergency medical gear, and spare fuel onto the snowmobile sleds. For our second foray, the party included me, John Penney, Susan, and Jim Lever. Russ, Stretch, Brad, and Judy remained in camp. That division placed one mountaineer, one emergency medical care provider, and one mechanic with each group.
Blazing Ice Page 17