When I ask for an explanation, Mike is quick with the math: The forests are fed by the abnormally high rainfall on the western slopes of the Olympic Mountains, ranging from about 80 inches [200 cm] a year near the coast to 150 inches [400 cm] or more along the river valleys in the foothills.
وهي تتراوح بين ٢٠٠ سنتيمتر في السنة على الساحل و ٤٠٠ سنتيمتر او اكثر عند السفوح على طول الاودية التي تجري فيها الانهر .‏