What does it mean when “they move with the steady momentum and perseverance of a mighty avalanche”

Ineed to have answers for numbers 2-4 reply to this question

Why did the united states become involved in the soviet-afghan war? the united states wanted access to the afghan oil fields. the united states wanted to retaliate against the soviet boycott of the 1984 olympics in los angeles. representative charlie wilson convinced congress to fund afghan resistance to soviet influence. president ronald reagan wanted to force the soviets to withdraw from afghanistan.

How have changes in transportation affected washington, d.c.