Because Mount McKinley National Park includes both northern and southern slopes of the Alaska Range, extremes in snowfall and precipitation are encountered in localities sometimes only 50 or 60 miles apart. One would expect that the snowfall would be heaviest on the northern slopes, but the reverse is the case. This is explained by the fact that the warm moisture-laden clouds sweep in from the Pacific Ocean and pile up along the seaward or south side of the lofty and frigid Alaska Range. The moisture is rapidly condensed resulting in a tremendous annual snowfall which at the higher elevations forms extensive glaciers. On the interior slopes the snowfall is comparatively light and the summers are relatively but not actually dry and warm. Thus Nucheck, in Prince William Sound, records a rainfall of 144 inches in 1 year, while on the interior side of the Alaska Range only 8 to 13 inches of rain, or about half of the yearly total, falls during the summer; and the snowfall during the entire winter is 30 to 85 inches.