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Note by David Albeck: I believe (as does Alan Smith, former President of the Mt Washington Observatory) that this article marks the first time Mt Washington was associated in print with the phrase "worst weather in the world." The article appeared in the December 1940 issue of Appalachia magazine, published by the Appalachian Mountain Club. At the time, publication without copyright notice placed the writing in the public domain, so I am reproducing this article in its entirety, including the original page numbers. I do not have good scans of the photos included with the article (they appear on non-numbered pages) but I include descriptions of these. The Figures (graphs) were redrawn by me as carefully as possible. The footnote on page 196 is part of the original article.

The author, Charles Franklin Brooks, was, in Smith's words, "Professor of Meteorology at Harvard University, first Director of Harvard's Blue Hill Meteorological Observatory in Milton, Mass., and ... a principal founder and the first Secretary (1919-1954) of the A[merican] M[eteorological] S[ociety]", as well as "the leader in the establishment of the Mount Washington Observatory". (Read Smith's article [linked above] for a fuller story in which others, notably Joe Dodge, also get due credit for the Observatory.)

The Worst Weather in the World

By Charles F. Brooks

Everyone knows that the climate on Mount Washington is severe. People like comparisons, however, and many questions are asked. Is it worse than the climate on other high mountains in eastern United States? Is it worse than the climate on the higher peaks of the Pacific coast, or in Alaska? How does the climate of Mount Washington compare with that of the high mountains of Europe, with the worst parts of the Arctic, for example, Svalbard, or Spitzbergen, as we may again have to call it with Germany now in control of Norway? Adelie Land, in the Antarctic, is the "Home of the Blizzard." Is the climate on Mount Washington worse than it is there? I am afraid that even local pride will not make it possible for us to say that Mount Washington has the worst climate in in the world; but comparisons are of interest.

The severity of cold climate is described in terms of (1) the penetrating qualities of the wind, (2) the lowness of temperature, (3) the amount of snow, and (4) the occurrence of freezing fog. The first three are present, in varying degrees, in our familiar New England blizzards. All are found on Mount Washington.

Figure 1 shows the average wind velocity each month in miles per hour. Figure 2 indicates the average number of days each month on which the wind reaches hurricane force.



The most extreme feature of the climate on Mount Washington is the velocity of the wind. Figure 1 shows the three-year average of the hourly wind velocity on the summit. This diagram, which shows average wind velocity of around 55 m.p.h. (miles per hour) from December to March, and more than 20 m.p.h. in the summer months, may not, at first blush, give the impression of the windiness which visitors to the summit have experienced. At lowland stations, however, the average wind velocities are generally in the neighborhood of 10 m.p.h., with higher values, up to 14 m.p.h. or more, only at exposed points on the coast, such as Cape Cod, Nantucket, and Cape Hatteras. Thus, the wind on Mount Washington averages something like four times the velocity of the lowland stations. This greater velocity, however, is not the measure of relative windiness. From a personal standpoint, we feel the wind as the pressure of the air upon us. The four times greater velocity on Mount Washington, allowing for the three-fourths density of the air at that level, gives Mount Washington a wind pressure of about twelve times that at the lowland stations.

As with any other meteorological element, it is not so much the average that counts, as the extreme conditions. Figure 2 shows the number of days per month on which the wind reached hurricane force (75 m.p.h.) in the years 1938 and 1939. From November to April a wind of this velocity occurred, on the average, at least every second day. In March, the windiest month, the wind reached hurricane force as often as two days out of every three. Winds of 100 or more m.p.h., which have an actual push nearly twice that of a 75 m.p.h. wind, have been recorded during the years 1932 to 1939, as follows:
Wind Velocity (m.p.h.) Hours Recorded
100-109 385
110-119 208
120-129 79
130-139 23
140-149 6
150-159 7
160-169 0
170-179 1

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The greatest extremes of wind velocity, measured for periods of less than an hour, have reached the neighborhood of 200 m.p.h. This velocity exerts a force four times that of a 100 m.p.h. wind. During the last eight years the heated rotation anemometer has shown an extreme maximum, in a fraction of a second, of 231 m.p.h. on April 12, 1934, and 163 m.p.h. on September 21, 1938, during the hurricane. The latter figure occurred some hour and a half before the maximum velocity of the wind, which could not be recorded owing to the vibration of the anemometer and the anemometer tower. Other comparisons, however, led to an estimate of 189 m.p.h. as the true maximum vlocity during the hurricane. There is a false impression of accuracy given by the precise numbers 231, 163, or 189, for in winds of such severity no apparatus can record the air-flow more than approximately. Although the actual velocity of these extremes may be in error by 10 to 40 m.p.h., there is no question but that the strongest winds of Mount Washington, which are the strongest yet recorded by any rotation anemometer, reach the neighborhood of 200 m.p.h. The full force of such a wind exerts a pressure of approximately 80 pounds per square foot of surface. The maximum strength of the hurricane at Boston, wehre the extreme velocity was 87 m.p.h., was only 20 pounds per square foot.

The destructive effects of the hurricane winds on the forests in various ravines on the west and north side of Mount Washington, and the tremendous force brought against the Cog Railroad, the low trestle of which, though weighing 1100 pounds per running foot, was blown over by the wind,* indicate that the velocity of the wind in certain places, where it was concentrated by the topography of the mountain, may have appreciably exceeded the velocity on the summit.

The low temperature on Mount Washington, the second of the four elements of a severely cold climate, is a marvel to visitors ascending the mountain at any time of the year. The average temperature on the summit is some 25 degrees lower than it is in the surrounding valleys. Occasionally, it is 40 or even 45 degrees colder. Figure 3 shows the mean monthly temperatures on Mount Washington, computed from the complete records of the United States Signal Corps and Weather Bureau,
*See photograph in the June, 1939, issue of Appalachia, facing page 323.


Figure 3
Average Monthly Temperatures
on Mount Washington
1870 to 1892, and of the Mount Washington Observatory, 1932 to 1939. The mean temperature runs from about 5° F. in January and February to a maximum of 45° F. or a little higher in the summer months. The maximum and minimum curves represent the monthly extremes during the years 1932 to 1939. The highest tempearture in summer has reached 71° F.; the highest in winter, 45 ° F. The highest of the monthly minimum temperatures is below freezing. The lowest temperature in the last eight years is 46° below zero, a figure which was reached twice in the winter of 1933-34. IN 1872 a temperature of 49° F. below zero was recorded.

High winds and low temperatures frequently attack together. Whereas in the lowlands the lowest temperatures occur in the calm after a cold wind has blown, the coldest periods on Mount Washington are brought by the strongest northerly winds of winter. On both occasions when the temperature was below 40° below, in the winter of 1933-1934, the wind reached velocities in excess of 100 m.p.h.

Snow, the third characteristic of a cold climate, occurs on Mount Washington in all months of the year. In the winter months it is the chief form of precipitation. The water content of the snow, however, averages only about a third of the total annual precipitation. The snowfall on the summit averages over 200 inches per year. This measured value is rather uncertain, because the snow that falls is usually quickly blown away, and other snow taht has fallen elsewhere is blown over the summit. The snow plume from Mount Washington may be seen for many miles. Much of the "snowfall" of Tuckerman Ravine and even Pinkham Notch, several miles away, is second-hand snow that has been blown off the mountain by the violent winds.

Freezing fog, the last in our list of considerations to detemine the severity of a cold climate, is one of the most remarkable

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features of Mount Washington weather. When it is realized that the summit is in the fog more than half of the time in winter, and that the temperature is almost invariably below freezing, the importance of freezing fog as a phase of the climate can be appreciated. Even at the lowest temperatures, an apprecialbe portion of the fog, which is in reality a cloud enveloping the summit, is still in the liquid-droplet form. At a temperature as low as 46° below zero, the formation of rime, the ice deposit which comes from the freezing of these liquid drops as they strike cold objects, has been observed. These rime formations form an impressive feature of the witner landscape on the summit. Every object is coated with the firm, white covering, often beautifully feathered in appearance. After several days of freezing fog and high wind, the deposit of rime reaches several feet in length. Rime three feet long formed on the Yankee Network radio twoer during two days late in August this year. Five or six feet have been formed in a single night. Such considerable formations, however, occur only when the temperature is not far below freezing. The maintenance of recording instruments under such conditions is extremely difficult.

The cooling power of winds of such strength, at such low temperatures, and of the often accompanying snow and liquid droplets, might be observed with a katathermometer or frigorimeter (cooling rates of small, bare, warm bodies), but the figures would not be significant in a human sense because no one can go out in such conditions, at peril of freezing, without having complete wind-proof clothing and face protection. Almost as cold as the conditions under extremely low temperatures, are those when snow, and considerable wetness in consequence, accompany excessive winds at temperatures near the freezing point. In addition to the loss of heat from the body and clothing by radiation, conduction, and the blowing away of the heat by wind (the cooling power is about 100 millicalories per sq. centimeter per second at 32° F. and 100 m.p.h.), there is the loss of heat in raising any adhering snow to skin temperature and a greater loss in melting and evaporating it. As long as one's clothing stays dry, the rate of cooling is very much less than if it becomes wet. This is chiefly on account of the much greater conductivity of wet clothing and of wet skin. Thus, a wet condition at or near the freezing temperature may prove to have a


greater general body cooling power in a strong wind than a dry condition with an equal wind velocity at a temperature 20° to 30° cooler. It is the frequent combination of wetness and wind that makes climbing on Mount Washington so dangerous, not only in the spring and fall seasons, but also in the so-called warm season as well.

How do these climatic conditions compare with those on other mountains where observations have been made? In the eastern United States there is no mountain as high as Mount Washington until we reach North Carolina, where Mount Mitchell and some others reach a few hundred feet higher. The temperatures on Mount Mitchell are approximately 20 degrees higher and the winds there only about two thirds as strong. The snow and icing are correspondingly reduced. In eastern Canada, on the Gaspé Peninsula, there are fairly high mountains, and on the northern coast of Labrador the mountains rise to over 6,000 feet. We have no records and know of no reports of conditions on these mountains in winter. It is probable, however, that the Gaspé mountains, level for level, have as wet and windy a climate as Mount Washington, but not so cold, owing to the Gulf of St. Lawrence; and that the mountains in northern Labrador are on the whole less windy, less wet, and probably not much colder than Mount Washington, being fairly near Hudson Strait, from which direction winds colder than those which would reach Mount Washington would have to come.

The blizzards of the western plains have long had a deservedly bad reputation, though in more recent years, with the increased planting of trees, their sweep is not so deadly as it used to be. But Mount Washington need offer no apologies to the West. Sub-zero temperature, on our own major peak, with a wind of more than 100 m.p.h., air filled with blowing snow and freezing fog, can far outdo anything met on those open plains.

In the western United States, the Rocky Mountains reach much greater heights than Mount Washington. On Pike's Peak (14,110 feet), where the Signal Corps maintained an observatory for fifteen years, the temperature averaged 9° lower than Mount Washington, but the wind velocity was appreciably less, averaging some twenty to twenty-five per cent below that on Mount Washington. The extreme velocity on Pikes Peak, though something over 100 m.p.h., is appreciably less than the Mount

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Washington extreme. During this period, whereas the velocity of 187 m.p.h. (indicated), eqivalent to 140 m.p.h. (corrected), was observed on Mount Washington, the maximum on Pike's Peak was 150 m.p.h. (an estimated figure, since the anemometer flew away at 112 m.p.h.), equivalent to approximately 100 m.p.h. (corrected). Though Pike's Peak may be foggy for twelve days at a time in winter, these periods are at such low temperatures that there is little moisture in the fog. In the late spring and throughout the summer, fogs rarely occur on Pike's Peak. The climate is a fairly dry one on the whole.

On the coastal mountains of the West we have no records from the Cascades region above the middle levels on the lee side of the Olympic Mountains and on the west side of Mount Rainier. It is probable that winds well above 100 m.p.h. occur on the summit, though not likely equal to the winds on Mount Washington, for the horizontal gradient of temperature in this region is less than in New England. The amount of moist air which passes over the Cascades, however, is much greater than that over Mount Washington, as may be readily noted in comparing winter photographs of the summits of western mountains, such as Mount Hood or Mount Rainier, with those of Mount Washington. The rime formations on these western mountains are tremendous, extending at times to twenty-five feet to windward.

An observatory was maintained for a few years on Mount Rose (10,800 feet) in the central Sierra Nevada. It was an un-attended observatory, in which the records were obtained by an automatic instrument with a long-continuing clock movement designed by S. P. Fergusson. In the period from 1905 to 1907 the lowest temperature was 8° F. below zero and the highest 71° F. above. The wind in winter appears to average only 20 m.p.h., and in summer less than 10. In severe storms, however, it exceeds 100 m.p.h. An estimate based on the pumping of the barometer shows an extreme maximum of approximately 130 m.p.h. The precipitation on the high Sierra, as is well known, is very great, much in excess of that on Washington.

There are many mountain stations in Europe. The most famous is Sonnblick Observatory in Austria, at a height of 10,170 feet, which now has a fifty-year record. The temperatures there, however, are much milder than Mount Washington's, ranging from a minimum of 8° Fr. in February to a maxi-

[non-numbered photo page: full-page photo of rime on instrument tower, with summit buildings in background]
Photo by Harry Felsenthal
Such rime formations come from the freezing of liquid droplets in the fog as they
are blown against cold surfaces

[non-numbered photo page]
photo: person in dark cap, face covering, and jacket, each bearing many small white crystals of rime
photo: person leaning into the wind while trying to walk toward camera
Photo by Trask's Studio
Formed in a few moments while making an outside observation
Photo by Zellon
Summit of Mount Washington, winter of 1939-40


mum of 34° F. in August; the average for the year is 20° F. The absolute minimum temperature was 35° F. below zero, and the highest 57° F. The strongest wind there in fifty years was about 100 m.p.h. The mean velocity, however, is relatively small, averaging only 16 m.p.h. for the whole year.

At the more norther stations the temperatures naturally are considerably lower, the winds stronger and the moisture features greater. The very worst we have record of is from Mount Nordenskiöld, Spitzbergen, in north latitude 78°, during the International Polar Year 1932-1933. This observatory was at a height of 3,480 feet above sea level. The maximum velocity of the wind was 132 m.p.h. for a whole hour. This would correspond to well over 150 m.p.h. for an extreme velocity. While this does not approach the Mount Washington record, it must be remembered that this mountain is only about half as high as Mount Washington, and that on the latter records have been kept for a longer period of years. Heavy riming was frequent, the anemometers having to be cleared of ice on one third to two thirds of the days in winter, which corresponds pretty closely to the situation on Mount Washington. The temperatures averaged 13° F. for the year, from a low monthly mean of 3° F. below zero to a high of 31° F. above. The lowest temperature for the year was 27° below zero. Here, even in this exposed Arctic mountain, we find neither wind nor temperature as severe as on Mount Washington, nor the icing any worse.

It is probable that there are worse mountains than Mount Washington, but observations do not seem to have been made upon them. Those of Kamchatka, of the Aleutian Islands, and, especially, the great mountains of Alaska, may at times have more severe conditions than Mount Washington, but I am inclined to doubt it, notwithstanding their high latitude and stormy locations, except for the mountains rising above 15,000 feet, where temperatures lower than on Mount Washington must occur and with winds well in excess of 100 m.p.h. The same must be true of the highest of the Himalayas, above 20,000 feet; though mountains at 9,000 and 11,000 feet in China have been found to experience surprisingly low wind velocities and moderate temperatures.

In Antarctica, Little America's worst has been a combination of 58° F. below zero with a wind of 43 m.p.h.; and in Adelie Land,

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the "Home of the Blizzard," 28° F. below zero with a wind of 95-100 m.p.h., and the air thick with drifting snow. Little America's worst is roughly equivalent in cooling power to a temperature of 25° F. below zero with a 100 m.p.h. wind on Mount Washington. Without considering the cooling effect of the drifting snow on Mount Washington or in Adelie Land, the combination of 46° below zero and 95 m.p.h. wind on Mount Washington, with its less than sea-level air density, has practically the same cooling power as 28° below zero and 100 m.p.h. wind near see level in Adelie Land. Stated in terms of millicalories per sq. cm. per minute for a surface at body temperature, as computed by G. Schmid's modifications of Hill's katathermometer formula based on observations on the Zugspitz, in Bavaria, the figures show a cooling power at Mount Washington of 230, and at Adelie Land of 225 millicalories. These results, while of value as relative figures, are of questionable worth as absolute numbers, since the formula was based on weather much less severe than that to which it is here applied. When we add snow's voracious appetite for heat when coming in contact with the skin, the cooling effect of the moderate drifting snow on Mount Washington, 40, and of the severe drifting snow in Adelie Land, 77, the total cooling powers become 270 and 302, which makes Adelie Land at its worst about ten per cent more severe than Mount Washington. Both are bad enough. One member of the Mawson expedition, out in Adelie Land's worst, came in with large frostbitten patches on cheeks and temples; a member of the staff of the Mount Washington Observatory, perhaps better protected about the face, did not get frostbitten in Mount Washington's worst, though two climbers, less protected, got badly frozen, one of them even suffering frozen eyes. So there is little real difference between a cooling power of 300 and one of 270. Both are more than ten times what we consider as very uncomfortably cold (20) and twice Boston's worst cold wave (125) or blizzard (144).

Thus it appears that while we cannot claim that Mount Washington is at times colder than anywhere else on earth, the severy of its climate at the worst seems to be equalled or slightly exceeded only on the very highest mountains of middle or high latitudes and in Antarctica's "Home of the Blizzard."