The Western Homestead from Tribune, Kansas • 5

THE WESTERN HOMESTEAD. August 1896. these warm waves, ascertaining the verti level in the atmosphere. The warm, dry the nV i THE HOT WINDS OF THE PLAINS. BX CEO, CUKTI3.

cal temperature gradients throughout th ciunooK winas oi mo extreme nortnwest n- cjc; have been clearly shown to belong to this clas, and prepent the most striking, though perhaps not the only example of thit kind of winds that we have in the United States. Prof. Hawn, of Leavenworth, has presented the view that the summer hot flel a contain moisture to evaporate, they ne ther originate hot winds, nor can their vegetation, in general, be severely damaged by those elsewhere developed. Thus every inch of water in me ii help to postpone the development of hot wind3, and sfiurda a r.r"te..;iV run' 4 ho rnv- The characteristics of the hot winda of the plains may be summarized as follows: Direction. Hot winds are usually from the southwest, coinciding with the direction of the prevailing summer winda of middle latitudes; lesa frequently from the south or Boutheaht, and very rarely a hot wind may be experienced from the north.

Tim of Occurrence and Duration. Hot winds of the plains are of the same general ages. character of these chinooks; that they: An increase in surface moisture haa al-have their origin on the Pacific coast and ready cc. -ropaal ihv the Rocky Mountains to the divide, culture in K.inhas, fct.d civeu where they are at an altitude of from ih-u the hot wind ure already fee- period, and showing their relation to the amount of heat absorbed and the amount of heat radiated by the air each day, as contrasted with these conditions in a period of ordinary temperatures. The purpose of the present discussion, however, is not to elucidate the peculiar meteorological conditions which obtain during warm waves; but 13 simply to show why hot winds develop over the plains during such periods, and are not felt yond their borders.

When the warm wave extends eastward, the hot wind does not accompany it From the continental interior toward the more humid and insular climate of the Atlantic States the heat and dryness arc gradually and the dry, hot winds of the plains are replaced by a stagnant atmosphere of high humidity and with temperatures ranging from IX) degrees to 05 degrees. At the beginning of this investigation a quent and i i in the day of 10,400 to 15,000 feet; then, blowing towards some area of low pressure, they dtweend on the eastern side, and in the process of descent are heated dynamically to the temperature experienced in the hoi winds. This is only an outline of the theory, and many details are omitted but it can be sulliciently considered with only this skeleton presentation. In many cases the area of low pressure with which the hot winds are associated is so situated that they cannot originate in or blown down from the mountain wind? occur most frequently in July and August, but occasionally also in June and September. A period of not winds very generttllj- continues for about three days over extensive area-, and these winds have omttimes been reported to occur daily for two weeks with greater or less severity.

The typical hot wind almost invariably et3 in at 9 or 10 o'clock in the morning a-id continues until 5 or 5 :30 in the afternoon, when the peculiar heat is abated, although the wind may continue through the night with unabated force. Humidity. The extreme dryness of the hot winds is one of their principal characteristics. It seems probable that the average relative humidity is not higher than 20 or 2.1 per but no hygromelric observations have been made by our special Wind force. The force of the different hot wirds reported ranged between wide limits.

In some cases the wind was only a 'moJerate breeze," while in others it number of the -ries as to the origin of the hot winds were already at hand and in the absence of critical tests, each one seemed to have a good claim for accept ahce, because of making these winds anal oeous to well knewn hot winds in other the But ue rciitial southern Kansas in 1888, cited at the opening of this paper, and of a large portion of the State during the hut tunmer, iows that additional measures must be employed to preent if possible the recurrence of these disasters. The most important and effective measure to this end ii the development of methods of water storage und irrigation. This conclusion is enforced by all the observed data herein presented, and by the experience of communities where irrigation is practiced. If water can be stored in sunicknt quantity and used to keep the crop moist throughout what would otherwise be a pe.iod of drouth, the destruction now occasioned by hot winds will be prevented, and the hot winds themselves will be lessened, or may even practically disappear, if the area kept from drouth be stfficiently large. A second mausurc that hus been suggested is the planting of timber belts to act as wind breaks, and to equalize and increase the humidity of the climate.

The discussion of this proposition opens th3 question of the relation between forests and climate, a subject too broad and too complex to be adequately discussed in the last section of tnis paper. But in spite of countries. The first and most natural suggestion was, that the hot winds being southerly simply carry north with them the temper ature of a warmer climate, just as the cold region. Hence some of the hot winds would be excluded from the application of this hypothesis. Secondly, this theory, like the preceding, fails to account for the strik ng diurnal character of the hot winds.

All winds are subject to some diurnal variation in intensity by virtue of which they tend to have greater force during the day than at night. But in foehn winds this diurnal variation is usually very small. Now, our reports show that the extreme heat of the hot winds abates at sundown, while the wind may continue to blow with undiminished force. Hence, conclusively, the high temperature cannot be derived from dynamic heating, or it would continue with the wirda at night wave transfers masses of cold air from high to low latitudes. The Sicilian siroc co is a hot wind of this kind.

This hypothesis lays hold of one of the most important conditions of the warm wave, but it is inadequate by it-self to ex plain the pecul iar feat ures of the hot winds since the latitudes in which the winds could arise do not have normal tempera' tures above 100 degrees. Moreover, the at night as well as by day, just as in the case of the chinooks. configuration of the isotherms during hot- We now come to the third hypothesis wTind periods does not correspond to a sim which the diurnal iharacter itself of the pie progressive wind of high temperature subject to continuous cooling as it ad hot winds suggests and confirms. It is that the local heating of the surface Is the cause of the hot winds and furnishes the vances northward. source of their high temperature.

Kansas A modification of this suggestion is the hypothesis that the hot winds of Kansas originate in the hot, dry "staked plains" was a "strong wind," and in one case it ranged from a "high wind" to a gale. Evaporating Power. The high temperature, the dryness, and the velocity of the hot winds constitute all the factors that promote evaporation, and the resulting rale of evaposation under their influence is consequently exceedingly high. No quantitative measures of the rate of evaporation during hot winds are, however, yet at hand. Effect on Vegetation.

In rare cases hot winds may scorch and burn vegetation while there is still moisture in the soil for the plant to draw upon to replace that which transpires. "Wheat when in the milk, and corn just beginning to tassel or to are in critical stages, and nre especially liable to be injured by hot winds. But, in general, hot winds do not materially affect the crops until by their evaporative effect they have drained the soil of its nmisture. Before that, vegetation droops and wilts somewhat during the day, but recoyers at night; and upon cessation of the hot winds is generally found to be not seriously damaged. Bat when the hot winds and lack of rains have thoroughly dried the ground, then one or two and Dakota each develop its own hot winds, and cannot charf them to the ac or Texa3 and New Mexico, and conse crunt of its neighbors.

quently, that if a belt of forest trees could be planted so as to intercept these winds, Let us take a typical hot, wind and ex amine' in detail the process of its produc immunity from them would thenceforth be secured. This view was vigorously pre tton. As already stated, the necessary conditions are those of the "warm wave," namely, a diminished pressure to the northward, producing southerly winds sented by the Hon. Charles Francis Adams in a lengthy letter to the Kansas City Times in August, 1888, and for a time, at the risk in expressing views that are not accompanied by the arguments upon which they are based, I desire to state that the measure seems to me well of extended and careful experiment. With respect to the value of timber belts to agriculture, there can, I think, be no disagreement.

Their utility as wind-breaks is, I believe, unquestioned. It is stated that in Michigan the blizzard was formerly unknown, and that peach trees were rarely injured by th cold. But one winter after the lumberman had begun his work of deforestation, a Dakota blizzard found the open gate and ushered in a new climatic era. This initial blizzard was followed by others in succeeding years covering larger areas, and the peav.Ii crop is now only a memory in tne minds of the older inhabitants. This illustration of the value of trees as a wind-break in Michigan indicates how potent an aliy they might become in protecting the crops of Kansas from the attacks of hot windd.

This was proposed in the article by Charlea Francis Adams, but with the idea that the State should be feuced in on its southern border, in order to prevent the entrance of hot winds from the staked plains. We now know that Kansas breeds its own hot winds, and that such a disposition of timber belts would be of little least, received a very general acceptance. which initially elevate the temperature above the normal. A cloudloss sky favors an intense insolation, as a result of which It is, at first sight, most plausible hy pothesis. The "staked plains" of western the dry ground is soon raised to an ex Texas are practically deserts hot and dry, The hot winds of Kansas blow directly from that quarter, the southwest.

Ergo, trcme temperature, and the air is heated from it by radiation, reflection and conduction. The resulting diminution of the hot winds come from the staked density due to the rise of temperature fur plains. To tebt this explanation was one nishes impetus to previously existing of the primary objects of the present investigation, and I believe that the materi horizontal cum nts, and by 10 o'clock in the morning the hot wind is fully develop al which has been collected furnishes con ed. Hundreds of miles of hot dry earth ducive evidence of its insufficiency. In contribute to maintain ana teea tne cur the first place this hypithesis applies only rent, and gathering strength as the sun to Kansas hot wi d3, and furnishes no ex mounts higher, the hot wind swe'epa over days of hot winds wither and Btirivel up the crop3 bejcnl possibility of more than partial recovery.

An attack of hot winds is usually found to leave some fields in much worse condition than others, and careful observation seldom faild to reveal the cause cithe difference. All circumstances that conduce to ilim'nish evaporation are most potent factors in preserving a crop of corn or wheat through a tryiu period. Freedom fn weeds, deep plowing and frequent cultivation which break up capillary ducts the soil, a sandy rather than a clayey surface soil, a subsoil of hard-pan which stores up the rain-waters for the crops to draw upon in critical periods these are some of the conditions which diminish the rate of evaporation and de- planation of thi Dakota hot which o2nur independently of the former. Con the defenseless prairie. Neither hills nor forests rise in its path to break its power sequently we would have to have two dif service.

As a shield from hot winds, strips of timber at small intervals would or dispute its sway, and with no enemy save the tardy rain-cloud, the fetid blast be of more value than larger wooded tracts ferent theories to account for essentially identical phenomena. Secondly, the "staked plains" theory breaks down even as an explanation of the origin of the hot sucks out tne lite-sap or tne growing at greater distances. It is frequently noticed that the outer rows of a corn-field grain. Thus the crops which should have returned a harvest to the farmer in r'pay ment for his toil are desiccated and with ered in a day. exhaust the force of the hot winds and serve to protect the inner portion.

Hence, if the field ere skirted by trees the entire The surface soil is heated to the high winds of western Kansas, when it is tested in the light of their diurnal periodicity. No feature of the hot winds is more uniformly confirmed by the observers than their forenoon development u.nd their afternoon bubsidence. Now, in order to reach western Kansas at 10 a. the hour acreage would be protected. temperature necessary to the development Secondly, as to the effect of forests on lay the beginning or aroutn.

ine contrasted effect ot hot winds on two adjacent fields may generally be traced to a difference in one or more of these conditions. of hot wind9 only where tho ground is dry, me sun's neat tailing on p. moist sou is the humidity of the air and soil, the very existence of any considerable number of vigorous forest trees upon the western largely used in the work of evaporation, of their advent, the hot winds would have plains would itself be evidence that the whence the accumulati jn of heat and the rise of surface temperature which would take place on a dry surface is to a -great soil retained more water than at present. And if the ground were moist, the summer temperature in and about the fortstxl degree prevented. In support of this, we find that the hot winds do not arise when to start from the staked plains before midnight of the previous night 9 most unlikely hour for the development of a hot wind and travel all night without any material los3 of temperature.

Such a history is not only highly improbable, but it is not confirmed by the testimony either of travelers or resident observers. The belt of country between the "staked plains' area would be lower and the air more humid. All these beneficial effects It appears from this summary that the destructive hot winds have few abnormal features. Their direction conforms to the surface pressure gradient, and their velocity is not markedly different from that of the usual winds experienced on the plains. The hot winds of the Kansas, Nebraska and Dakota prairies occur under the same and are of the same generic character as the "warm wave" or 'heated term" of the Eastern States.

In fact, the propagation of the over-heated the soil is moist, and that a rain-storm quickly brings them to an end. Converse- elts amount to a virtual modification "of the reports bear uniform testimony to the climate, and the question is still an the feet that periods of dpouths are peri open one, whether it can be effected. We can plant the trees, but will they grow for ods of hot winda, and the more prolonged us when planted? The plains region ia not one from which the timber haa lately been cut off, and the absence of forests ia the more continuous and intense do they become. Manifestly, immunity from hot winda cannot be secured so long as there is no way of obtaining, immunity from drouth. On the other hand, all method8 and central Kansas nas not sent out any report of such nocturnal hot winds as this theo would demand.

I pass now to a second hypothesis as to the origin of the not winds. This brings tl into the general class of foehn winds, winds which their heat dynam area from west to east can generally. vbe plainly traced on the daily weather ps of the Signal Service. At another time I hope to Btudy the special barometric and thermal condition? due to essentially unfavorable climatic conditions. That a chanse of cli ma's nan of cultivation which directly or indirectly help to increase or retain the moisture in be effected by forestation is dismissed bj many with the proposition, which ia ically by descent from a relatively high which obtain during tne prevalence 'I.