The Winter Fortress

by Neal Bascomb

  A few days before, Sørlie had been approached by one of his colleagues at Vemork, Harald Selås, who asked him to find the answers to a list of questions about guard rotations and the like at the plant. Clearly, there was sabotage planned, and Sørlie suspected his friends up on the Vidda were most likely involved.

  The answers to the list of questions in his pocket, he headed over to the base station of the Krossobanen, the cable car that brought Rjukan residents up to the Vidda. He arrived early and waited, searching the darkness, unsure who was coming to meet him. Then his old friend Claus Helberg approached from the Ryes Road, a series of switchbacks beneath the cable car line that had been cut through the woods during its construction.

  “I’m glad it’s you,” Helberg said.

  Sørlie brought Helberg back to his house and asked him to wait in the garage until the birthday party was over. Then they went up to his room. The family’s Gordon setter, Tarzan, barked madly at the stranger’s presence, but nobody came out of their rooms to investigate.

  The two men went through the list, notably the number of soldiers on guard at Vemork at any one time (fifteen), their rotation schedule (every two hours), the security on the suspension bridge (reinforced in the past month), and the patrols around the grounds (the route went past the railway-line gate). The only viable path into the plant, they agreed, was across the bridge, even though it was defended. As for the approach from the gorge, the two locals recalled the time when a car had plummeted off the Møsvann Road into the gorge, and the rescuers had needed ropes to reach the driver and passengers. It was simply too steep to climb.

  After they had gone through the information, Sørlie gave Helberg some leftover “beef” (spiced and fried yeast dough) in the kitchen, which he devoured. He stayed overnight and, in the still and dark of morning, slipped out of the house and headed up to Våer along the main road.

  Sørlie watched him go, fearful that he might never see him again.

  Throughout Friday, Helberg waited in the Fjøsbudalen cabin for the others to arrive. There was nothing more in the cupboards than some dried syrup riddled with ants. High up in the isolated side valley that ran down to the road to Lake Møs, the cabin offered a fine view of Rjukan in the far distance. Vemork, two miles away on the opposite side of Vestfjord, was not visible.

  At 6:00 p.m. the others arrived, led by Poulsson. They had spent the night at Poulsson’s brother-in-law’s place on Lake Langesjå, where Poulsson had found some new skis and woolen stockings. He also found a bottle of Upper Ten whiskey, but they decided to leave it there for when they returned—if they returned.

  The nine men barely fit inside the snug cabin; if they were to sleep, they would have to do so in turns. When a rotating one-and-a-half-hour watch was in place and the windows blacked out, they sat down to go over the new intelligence. Helberg began. Machine guns and floodlights were mounted on top of the main building. Two guards patrolled the suspension bridge. The guardhouse was on the Vemork side, where a third soldier had an automatic weapon and access to an alarm, easily activated if there was trouble on the bridge. If the alarm were raised, the entire area would be lit up—including the penstocks above the building, the suspension bridge, and the road through Våer—and the soldiers in the barracks at Vemork would be alerted, as would the garrison in Rjukan.

  The gorge was unguarded, and the entrance to the railway line was only lightly patrolled, but as Helberg explained, this did not make the approach a better option. The climb from the gorge to the railway was all but impossible in summertime. In the dark, in the ice and cold, there was surely no way it could be done.

  Idland argued for the bridge approach. It was swift and sure. They would kill the guards, then storm the plant. Poulsson and Helberg doubted it would be so easy, but agreed that the bridge was the better of the two options. Rønneberg sided with them. Only Haukelid was convinced that they should attempt the gorge approach, as Tronstad had recommended. Otherwise, he said, they would likely face a pitched battle to reach the high-concentration plant.

  From his rucksack, Rønneberg produced a set of aerial photographs of Vemork, taken during the previous summer. The team had studied these with Tronstad, and the professor had suggested places to cross the gorge and points along the railway line where they could hide before the attack. Rønneberg spread the photographs out on the table.

  Haukelid pointed to some scrub and trees growing along the sides of the gorge. “If trees are growing,” he said, “you can always find a way.” The others nodded in agreement. Rønneberg instructed Helberg to return the next morning to scout a potential route that would keep them from plunging to their deaths. He would need to go in daylight if he was to have a chance of determining one. They all understood that the operation would be in jeopardy if he was spotted.

  In Kummersdorf, Kurt Diebner and his team were refining their new reactor design. The central concept was to suspend a lattice of uranium cubes in a sphere of frozen heavy water. The setup was far simpler than their previous experiment, and the architecture of the cubes and moderator were better suited for bombardment.

  Abraham Esau, the new head of the Uranium Club and now Diebner’s boss, had made it clear that he needed results. “If you make a reactor, and you put a thermometer in it, and the temperature increases only one-tenth of a degree,” he said, “then I can give you all the money in the world—whatever you need.” On the other hand, he warned, if this could not be achieved, then they would not see another pfennig.

  As it was, money was not exactly pouring in to the program. Paul Harteck had developed an ultracentrifuge design to enrich U-235 that showed great promise, but he had been unable to get the funds he needed for an expansion. Diebner had also seen requests for additional heavy water supplies hobbled by limited finances. Two hydrogen electrolysis plants were found in Italy that might be able to provide limited amounts of heavy water of 1 percent purity. This could then be enriched in Germany to almost 100 percent, but only if the pilot plant built by IG Farben outside Leipzig was constructed at full scale. This project was on hold while Norsk Hydro was continuing to provide heavy water at a limited cost to the war effort.

  For his next test, Diebner secured, with Esau’s approval, a special low-temperature laboratory in Berlin and some of Heisenberg’s heavy water supplies. Given that Vemork was producing close to five kilograms of the precious fluid a day—and that the nearby Såheim and Notodden plants were shortly to add significantly to this amount—Diebner could scale his experiments up quickly if his design proved its merit, and resources and manpower would pour in to the program once he produced a self-sustaining uranium machine.

  Interest in the potential fruits of atomic fission certainly seemed renewed in many quarters. Hermann Göring, who now oversaw the Reich Research Council, described its atomic research as of “burning interest,” as it was indeed for high officials in the Kriegsmarine, the Luftwaffe, and the SS. A uranium machine would bring many new champions.

  An hour after sunrise on Saturday, February 27, Helberg headed down toward Vemork. The temperature was mild, but the wind warned of an approaching storm. Because it was the weekend, and because he was in civilian clothes, his hiking and skiing in the valley would not attract undue attention. Passing Våer, he continued east through the woods above the road that ran along the northern wall of the valley between Rjukan and Lake Møs. There he came upon a power-line track that he knew ran parallel to the road.

  He followed this track until he sighted what might serve as a path down into the gorge. Stashing his skis and poles, he made his way through the trees and crossed the road. He slipped and slid down the slope, using juniper bushes and pine branches to control his descent. Eventually he reached the Måna River. Its surface was frozen, but the ice was very thin in places. In a warm spell, the river would be impassable.

  He hiked back and forth along the river’s edge, trying to spy a manageable route up to the railway line. Finally, he spotted a groove in the cliff that was somewhat less ste
ep than the surrounding wall. Some bushes and small trees rose out of the splintered crevices of rock, and they could provide hand- and footholds. Weather and luck permitting, he figured it was worth a try.

  Smiling broadly, he returned to the Fjøsbudalen cabin after lunchtime to give his report. “It’s possible,” he said. Overwhelmingly, the team agreed with the proposal to climb up the gorge on the night of the operation.

  Now they could turn their minds to how they were going to get away.

  They were confident that, whether they arrived quietly or not, one of them was sure to reach the target and set the charges. Nine heavily armed and well-trained commandos, comfortable in the terrain and eager to serve their country, were a good bet against thirty German guards.

  However, even though they did not voice it, most of them, including Rønneberg, believed that the odds of their getting away afterward were thin at best. Once the plant blew, they were not likely to get far. Either they would be trapped at Vemork or hunted down by the hundreds of soldiers garrisoned in Rjukan. Even so, not one of them had a death wish, nor was it good for morale to think of their mission as a one-way ticket.

  Rønneberg wanted his men to feel like they each had a say in the final plan. As with the approach, there were a few options. They could climb up the penstocks and escape that way, but the steep ascent and the presence of guards at the top, not to mention minefields, made this an easy option to cross off the list. They could retreat across the bridge and head straight back into the Vidda. This was the fastest, simplest escape. However, they would have to kill the German guards, guaranteeing even harsher reprisals on the local population. And their pursuers would know which way they had gone.

  Their third option was to go back down the way they had come. They could return to the Fjøsbudalen cabin or, as Helberg suggested, go in the opposite direction down the power-line track, to Rjukan, and then hike from the Krossobanen base station to the plateau along the zigzagging Ryes Road. The Germans would have no idea where to look for them. This route demanded another descent and ascent of the gorge, then a punishing climb. Further, if they were seen, they would be heading straight into the enemy embrace of the Rjukan barracks.

  Once all the possibilities had been sketched out, Rønneberg gave each man a vote. It was a close call. The majority favored leaving the way they came, then ascending to the Vidda underneath the Krossobanen.

  The plan was set. Rønneberg told them that the operation would start at eight o’clock sharp that night and that they should rest as best they could.

  Soon after, Idland drew Rønneberg to one side. Since he was first chosen for Gunnerside, the heavily built former postman had known that the retreat to Sweden was going to be a problem. He was sufficiently skilled to reach Vemork, and he was as fit as anyone else on the team, but he was convinced that the 280-mile trek to the border would prove too much for him. He had always figured it was going to be a one-way journey, he said, and now he wanted his leader to know that he did not intend to slow down the team if they had the chance to escape. He would find his own way. “Nonsense,” Rønneberg said flatly. “You’ve kept up with us until now, and you can keep up with us to Sweden.”

  For this decision the young leader did not offer a vote.

  That same afternoon, at 4:45 p.m., Leif Tronstad caught a train to Oxford at London’s Paddington station. He was on his way to St. Edmund Hall, the oldest academic gathering place at any university anywhere in the world. For a brief spell, he would try to avoid all war news and think only of science and history and the pursuit of knowledge for its own sake. It would not be easy. Two days before, he had finally received word that Gunnerside had survived their first days on the Vidda and had met up with Swallow. “Everything in order,” Haugland had sent. “Spirits are excellent. Heartiest greetings from all.”

  So while he wasn’t expecting another message from Gunnerside until the operation was complete, Tronstad was hoping for news from Odd Starheim and his forty commandos. From the start, the Carhampton operation had been plagued with bad luck. Their first attempt to commandeer a convoy of ships had been thwarted by a blizzard. Their second had ended in a furious gun battle, followed by a manhunt. Starheim and his men had hid in a remote valley farm. Instead of abandoning the operation and trying to find a way back to Britain, Starheim insisted they attempt another target. He would not leave Norway without having achieved something—Marstrander and a host of others had lost their lives bringing them there.

  Tronstad and Wilson had assigned them a raid on some titanium mines, but the terrible winter weather delayed them—and for too long. The Gestapo closed in, and Starheim and his men fled again. On February 25 the Royal Navy dispatched a boat to pick them up, but a North Sea storm had forced it to turn back. Now the men were without food, equipment, or shelter, and the German noose was tightening. According to the latest cipher message, Starheim was going to attempt to seize a coastal steamer to escape to Scotland.

  When Tronstad arrived in Oxford and entered into the cloistered and peaceful world that had once been his own, he had trouble settling, not least because of reports he had received of a recent speech by German propaganda minister Josef Goebbels. “Do you want total war?” Goebbels had demanded of his audience, packed into a Berlin stadium in mid-February. The crowd responded with raised salutes and a resounding “Yes!” Goebbels then shook both fists and shouted: “From now on, let our slogan be ‘Rise up, people, and unleash the storm!’”

  Tronstad knew the Nazis would follow through on that promise as soon as they had the means to do so.

  Sitting outside the Fjøsbudalen cabin, wearing his British uniform, Haukelid quietly smoked a cigarette, ready for the mission that was still a few hours away. Beside him, Helberg and a couple of the others were oiling their pistols and Tommy guns.

  Their silence was broken by the approach through the woods of a young man. There was a scattering of cabins in the high valley—they should have expected one or two of them to be occupied over the weekend. The men slipped unseen into the cabin and alerted the others. The stranger knocked once on the door of the cabin. Before he could knock again, the door was thrown open, and Poulsson grabbed him by the throat and dragged him inside.

  Haukelid pressed a pistol into his belly. “Who are you?” Poulsson demanded.

  The man recognized his captor: “We were in the same class at school, Jens.”

  “Kåre Tangstad,” Poulsson said, releasing him. “Yes, I remember you.”

  Tangstad explained that he had only come looking for the loan of a snow shovel. He, his fiancée, and another couple were staying up in the valley for a couple of days. Poulsson told him in no uncertain terms that he was to stay in his cabin, with the others, for the whole of the weekend and that they were not to leave for any reason. Tangstad agreed.

  Haukelid watched him leave the way he had come, disappearing into the forest. He imagined being in the woods for a simple weekend with a girl and some friends—and felt at an enormous remove from such a normal life.

  The saboteurs had a hurried conversation about whether or not their neighbors could be trusted. Rønneberg decided to go over to their cabin to talk with them. Their assurances that they were good Norwegians and opposed to the occupation convinced him that they posed no threat. Parting, Rønneberg called out, “God save the King and Fatherland!” He might well have added the hope that God would look after his team that night.

  17

  The Climb

  * * *

  AT 8:00 P.M., white camouflage suits covering their British Army uniforms, the nine men skied away from the cabin in silence: Rønneberg, Strømsheim, Idland, Storhaug, Kayser, Poulsson, Helberg, Kjelstrup, and Haukelid. They were armed with five Tommy guns as well as pistols, knives, hand grenades, and chloroform pads. In their rucksacks they carried the explosives for the attack and everything they needed for their retreat into the Vidda: sleeping bags, rations, maps, and other survival gear. Cyanide pills were hidden in their uniforms, to be swallowed
in the event of their capture. The men knew all too well what became of those who were brought in for interrogation by the Gestapo.

  Helberg led the way down Fjøsbudalen Valley. The moon, hidden by low clouds, shone dimly, and Helberg navigated mostly by memory and a natural feel for the terrain. He kept a steady pace, sweeping around boulders and twisting through the scattering of pine and mountain birch. The others followed closely behind, the cut of their skis barely a whisper through the snow.

  Rønneberg had made clear that, no matter what unfolded, no matter whether he or anyone else on the team was killed or wounded, those who were able were to “act on their own initiative to carry out the operation.” Destroying the heavy water plant was paramount. Each man knew what to do once they arrived at the target. They had practiced their SOE training many times on schemes against mock targets. Stop and listen frequently. Take short steps, lifting feet high. Move silently. The covering party—the most heavily armed—went in first. To prevent accidental shots, no guns were to be loaded until necessary. Two demolition teams, two sets of charges. Rendezvous after the sabotage, passwords to be called out. Now their mission was underway. They were finally getting their opportunity to strike a blow against their country’s occupiers, and from everything they had been told, Vemork would be a significant blow.

  Roughly a mile from the cabin, the valley became steep and thick with boulders and shrubs. The men unfastened their skis and hoisted them onto their shoulders. They continued on foot. When they were not sinking up to their waists in the snow, they slipped and scrambled to remain upright, their heavy rucksacks and weapons throwing them off balance.

  An hour into their descent they reached the Møsvann Road. Free of the woods, they saw Vemork, a mere fifteen hundred feet across the gorge—were they able to fly. Even at that distance, they could hear the hum of the power station’s generators. After months of thinking about this leviathan, months of examining every facet and corner of it in blueprints and in photos and in their minds’ eyes, there it was. To a man they stood mesmerized by the winter fortress. It was no wonder, Haukelid thought, that the Germans felt they needed only thirty guards on hand to defend it.