One of the Northern Hemisphere's long-lived, winter-weather features is the so-called Siberian high. As winter deepens, this dense mass of cold air becomes a potent weather maker for the Arctic and even temperate North America.
In the Jan. 15 Geophysical Research Letters, scientists report that the strength of the Siberian high is linked to the amount of early-season snow cover in this Russian region. The researchers, led by Judah Cohen of the consulting firm Atmospheric and Environmental Research in Lexington, Mass., made the connection after analyzing data collected from 1972 to 1999.
As autumn arrives in northern Eurasia, the Siberian high begins to form and then strengthen. Because the dense air typically extends only a few thousand feet high, it usually doesn't cross over the mountains into eastern and southern Asia, Cohen says. Instead, it moves westward into Europe.