– After an emergency landing on a Swiss glacier, the group of 12 Americans drank melted snow and survived on rations of one chocolate bar a person until daring pilots shuttled them to safety after five days marooned on the ice.

Relics of that harrowing adventure and the rescue of all those onboard, including an 11-year-old girl and the captain’s mother, resurfaced after 70 years this month when scorching summer temperatures caused the ice to recede.

That uncovered a large part of the wreckage of the U.S. Air Force transport plane, including a wing and items from the cabin, like canned food and clothes hangers. The glacier’s inexorable slide had moved the plane debris about 2 miles.

Parts of the C-53 aircraft, also known as a Dakota, had been discovered over the past 20 years. But the heat waves washing over much of the continent this year have permitted the retrieval of many more artifacts that recount the death-defying story of the 1946 flight.

The plane had been heading to the southern French city of Marseille from Munich, carrying American officers and family members. The pilot, Capt. Ralph H. Tate Jr., found himself navigating among snowy peaks in turbulent weather and was forced to make a risky crash landing on the glacier.

One passenger, a sergeant, broke his knee in the crash, but the others had relatively minor injuries. Snow covered the plane and formed a kind of igloo that helped them survive, Swiss rescuers said, adding that the plane had “miraculously missed a crevice 250 feet wide and 50 feet deep.”

The rescue operation was extensive. About 150 U.S. troops stationed in Italy arrived in the village of Meiringen, at the foot of the glacier, to search for survivors.

But it was two Swiss pilots who became the mission’s heroes, flying German-made reconnaissance planes fitted with skis to land on the ice and pick up the Americans. The planes could carry only two stranded passengers at a time, however, so numerous gut-wrenching trips were needed to transport everyone to safety.

The 11-year-old onboard, Mary Alice McMahon, smiled as she got out of the rescue plane, chewing a piece of gum.

The operation — the first time the Swiss air force used planes to carry out a mountain rescue — became a milestone in Swiss aviation history.

The survival of everyone onboard continues to amaze experts. “It was the most improbable story in the history of international aviation, for a passenger aircraft cruising at a speed of 280 kilometers per hour [more than 170 mph], to hit the ground with everyone on board unhurt,” said Peter Brotschi, a Swiss aviation expert.