the aftermath of the Ranrahirca slide. American climbers David Bernays and Charles Sawyer observed, in the aftermath of this slide, "a massive vertical slab of rock being undermined by Glacier511" posing the threat of a much larger collapse. The overhanging cliff was as much as high in places and the rock was described as being "pervasively fractured." Although the risk to Yungay was remote, the town could be threatened if a "sufficiently large avalanche" were to spill over the ridge to its east. The Americans' findings were reported on September27, 1962, in the El Expreso newspaper, under the headline "Dantesque Avalanche Threatens Yungay." Local authorities ordered this information to be retracted, and discouraged citizens from speaking about the threat, in order to prevent panic: "Anyone who spoke in favor of the Americans' conclusions would be charged under the Penal Code for disrupting public tranquility." The director of the regional Lakes Commission, Miguel Eliás Pizarro, was asked to "provide an expert analysis." Pizarro "dismissed the American mountaineers' statements as outlandish, hurried and uninformed" and stated that Yungay was in no danger, being well out of the path of the 1962 slide. Bernays and Sawyer were reportedly threatened with arrest, and they soon fled the country. Prior to that, Bernays had attended a public meeting in Huaraz where he called the Expreso coverage "exaggerated", though he did not deny the possibility that a large enough avalanche could affect Yungay. This same glacier would be the origin of the much larger collapse that destroyed Yungay eight years later. Earthquake and landslide At 15:23 on Sunday, May31, 1970, the Ancash earthquake (also known as the Great Peruvian earthquake) struck off the coast of Peru with a moment magnitude of 7.9. The shaking dislodged a slab of rock about wide from the western face of Huascarán's north peak, at an elevation of roughly . The rockfall occurred almost immediately after the shaking began, with witnesses comparing the sound to a gunshot or explosion. The fall triggered an "enormous dark cloud of dust" which rapidly blocked the view from below. The rock fell some vertically before landing on Glacier511 and sliding nearly down its surface, accumulating a large volume of firn snow as it went. The initial ice-rock avalanche volume was at least 25millionm3 (33millionyd3), and grew rapidly in size as it fell down the steep Llanganuco valley, picking up large volumes of dirt, loose glacial