Ojos del Salado was first climbed in 1937, the same year that hot vapors and sulfurous gases were seen escaping from one of the volcano's cones. This occurrence was observed again in 1956. In 1994 the volcano spewed a visible column of water vapor and sulfurous gases. The height of Ojos del Salado is not debatable, but whether it is active is subject to debate among geologists. Some consider the volcano extinct in spite of its recent activity because its last recorded eruption was 10,000 years ago. Others point to the recent recordings as definite signs of activity.
