There has been activity at this site as recently as 7,600 years ago, though more likely less than 1,000 years ago. Kostal Cone is too young for the commonly used potassium-argon dating technique (usable on specimens over 100,000 years old), and no charred organic material for radiocarbon dating has been found. However, the uneroded structure of the cone with the existence of trees on its flanks and summit have it an area for dendrochronology studies, which reveals the growth of tree-ring patterns. Tree-growth data has revealed an age of 400 years for Kostal Cone, making it the youngest volcano in the Wells Gray-Clearwater volcanic field and one of the youngest volcanoes in Canada.