Question

Siberian Express is the term used when:

a. an outbreak of bitterly cold air from Canada intrudes over a large part of the United States.
b. an mP air mass from the north Atlantic enters New England and generates snowfall.
c. a modified air mass originating in Siberia reaches the Pacific Northwest.
d. an unusually cold air mass enters the Rocky Mountains.

Answer 1

The term 'Siberian Express' refers to a modified air mass originating in Siberia that moves into the Pacific Northwest of the United States, bringing with it extremely cold temperatures as a result of large high-pressure systems over Siberia.

Step-by-step explanation:

The term Siberian Express is used to describe a weather phenomenon where a modified air mass originating in Siberia reaches the Pacific Northwest of the United States. This occurs when the frigid air masses that build over Siberia, which is a vast and generally cold region, move across the Bering Strait and into Alaska and Canada before sweeping down into the continental United States. The Siberian climate is noted for its intensely cold winters and due to its northerly latitude, northern Russia, which encompasses Siberia, experiences frigid air masses that travel southward in the winter.

Siberia itself is a remote and sparsely populated region, larger than the United States but with a much smaller population, and its geography greatly influences weather patterns due to features like the Siberian High, a high-pressure system that contributes to the spread of cold air.