Some sediments were deposited during periods of much warmer climate than today. This story is told, in part, through the fossilized remains of plants and animals preserved in the region's rocks. Skeletons of marine animals, known only to inhabit warm waters, are preserved in Canyon shales. Corals, fossilized in limestone, can be found throughout the southern portions of the park. Permafrost Even though we are between glacial ages at the moment, the climate of the northern Yukon is still a harsh one.
Winters are long and cold and summers are all too short.
The average temperature over the year is so cold that the majority of ground in the park is permanently frozen. Despite this, the northern Yukon in summer can be surprisingly lush and teeming with life. Any precipitation that does fall, along with the melting snow, sits on the surface. Water is then available for a range of plants and animals that would not otherwise survive. As well, the warm summer sun is able to melt the upper layer of ground to varying depths, thereby freeing up soil for root development.