NATIONAL PARK SERVICE Fauna of the National Parks of the United States No. 3 Birds and Mammals of Mount McKinley National Park

CLIMATE OF MOUNT MCKINLEY NATIONAL PARK

SINCE 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.

As a result of these conditions we have a reversal of the general rule which is that in northern latitudes animal life is more abundant on the southern than it is on the northern exposures. People visiting the park, therefore often show surprise when they find not only big game, but small animals as well, most numerous on the northern and supposedly unfavorable side of the Alaska Range.

Again, because of the atmospheric conditions, travel both by land and by air in this area is restricted at present almost entirely to the northern side of the Alaska Range during the summer travel season.

It so happened that a mild winter with relatively light snowfall was followed by an early, warm, and fairly dry summer in the McKinley region in 1926, while in 1932, the summer season, following the most severe winter in 40 years, was late, cold, and wet. I thus had an opportunity to experience both climatic extremes in my field work.

The self-recording minimum thermometer left near Browne's Tower, at about 15,000 feet, on Mount McKinley by the Stuck-Karstens party in 1913 was recovered by the Liek-Lindley expedition when they climbed the mountain in 1932. This spirit thermometer was calibrated down to 95° below zero and the lowest recorded temperature was below that point. Harry J. Liek took the thermometer back to Washington, D. C. where it was tested by the United States Weather Bureau and found to be accurate. The lowest temperature that it had recorded was found to be approximately 1000 below zero.

Chief Clerk C. E. Richmond kindly supplied temperature records kept at park headquarters for several years, but the minimum daily temperature records obtained by Charles Sheldon at Toklat in 1907-8 (Sheldon, 1930, p. 394), are more typical of the major portion of the park, and they are given below.

Minimum daily temperature, above or below zero, at Toklat

Out in the park during certain winters the thermometer may drop to 65° below zero but it rarely stays as cold as that for any length of time. One of the longest "cool" spells Sheldon experienced on the Toklat came during the first week in November 1907, at which time the minimum daily temperature ranged from 260 to 360 below zero for a period of 7 days. Near Peters Glacier, at the north base of "Denali", Sheldon's records show that from December 26-31, 1907, the daily minimum temperature varied from 31° to 38° below zero. Contrasting with this, the daily minimum temperature dropped below zero at Toklat only during 14 days of the entire month of February 1908, whereas during the other days of the month the daily minimum ranged from 1° to 27° above zero.

The duration of the "summer season" in McKinley Park in 1932 was from June 14, when the last spring snowstorm left 6 inches of snow on the ground, to August 4, when the first fall snowstorm left several inches of snow on ridges down to the 4,000-foot contour line. At Wonder Lake, early in the morning of August 18, 1932, there was a thin sheet of ice about as thick as a window pane, over the nearby small ponds and along the margins of the creek.

Quoting from my field notes, the following account gives a fair impression of a typical summer day in Mount McKinley National Park.

SAVAGE RIVER, 2,800 FEET, JUNE 1, 1926.—Today broke clear as a bell. At 4 o'clock this morning the sun was shining brightly and snow-clad Mount McKinley from base to summit stood out against a deep blue sky in perfect snowy splendor (fig. 2). By 10 o'clock in the morning heavy storm clouds had drifted in from the southwest and by 10:30 o'clock both rain and hail began to fall with great violence. It rained hard at noon and again about 4 o'clock, but the clouds cleared off late that evening so that by midnight the sky was clear again.

Figure 2.—The best views of Mount McKinley are to be had early in the morning. "Denali" at 4 a. m.
Photograph taken August 17, 1932. W. L. D. No. 2840.

In July 1932, it rained for days at a time in McKinley Park. The "damp" condition prevailing along the Alaska Range in summer which is produced by the rain results in the shrouding of the mountain in clouds. In 1926, out of a total of 72 days' field work, we had just 8 good views of "Denali", while in 1932, I had 14 good Views of the mountain in the 110 days spent in the park. In the spring and fall visibility of the mountain is greater than it is in summer.