How deep can permafrost extend beneath Arctic tundra?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Rolling tundra in Alaska with red, yellow, and green fall foliage, set against rugged mountains with patches of grass and exposed rock. — Tundra Alaskan mountain and tundra vegetation in the fall.

Across much of the Arctic, permafrost typically extends to depths of 350 to 650 metres (1,150 to 2,100 feet). In specific unglaciated regions of Siberia, however, it can reach depths of 1,450 metres (4,760 feet). Other observations in northern Alaska and Canada suggest depths ranging from 800 to 1,500 feet, with the deepest known permafrost—exceeding 2,000 feet—also located in northern Siberia.12

The depth of this frozen ground is influenced by several factors, including local climate, vegetation, site-specific conditions, and the area's geological history, such as whether it was previously covered by glaciers or sea ice.2