On the Trail of the Devil Wind

On the Track of the Devil Wind

The year was 1934. In the eastern face of a 300-yard-long spur of the Castle Mountains, about 10 miles west of the Papago village of Santa Rosa, two workmen for an archaeological expedition camped in a large cave. It was winter; a relentless rain was falling outside, and they were cold. They had heard the legend of the cave, but their predicament apparently dulled their memory. So, without much thought, they built a fire with some ironwood branches. Food and the delicate warmth of the flames soon lulled them to sleep. Suddenly, an explosion of firebrands filled the air, and menacing flames by Sherwood B. Idso swirled about them, setting their blankets ablaze. Still drunk with sleep, the men tried desperately to react rationally to the cascading messages of their overloaded senses. But what could they do? Fumbling about in confusion and semipanic, one of them grasped the large flat stone that lay nearby. Remembering its purported powers, he flung the talisman onto the flames .. their fury abated; the spirits of the cave were appeased. Ventana Cave. Hewultki. Well did the Papago Indians call it "Whirlwind House" and "Home of the Dust Devil." For Wind did live there; and daily in

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summer small dust devils would issue forth from its mouth to grow into tall columns that marched for miles across the desert. Had not each son been told the story by his own father, while gathering the fruit of the giant saguaro?

It was true; it had always been so. The day was bright and sunny some 40 years later when my young sons and I ventured forth onto the Gila River Indian Reservation just south of Phoenix. Like the Papagos of untold generations before us, we too had come to admire the beauty and majesty of the desert dust devil.

I pulled the car to the side of the road. Almost before it stopped, my fourth-grader, Grant, jumped from the back seat and dashed out on the powdery mulch of the recently leveled field. There, a tiny column of dust began to rise before him.

"Dad," he shouted, "I've created a dust devil!"

Tumbling out behind him, eager to see what all the excitement was about, came Keith and Craig, Grant's two younger brothers. Together, they all raced along in pursuit of the meandering whirlwind. Suddenly, however, it stopped its lateral movement and began to stretch vertically and expand in diameter. Then came the sound. Imperceptible at first, it gradually increased in intensity, as the wind whipped the loose surface soil into a frenzy.

I shouted to the boys to dash into the funnel and release the colored balloons they carried into its swirling updraft, so I could photographically determine their rate of ascent; but my encouragement was to no avail. As the ominous vortex churned violently before them, their own better judgement told them that here was a phenomenon to be observed from a respectable distance.

Musing upon the reactions of my young sons, my mind wandered back to Ventana Cave and the Papagos who christened it Hewultki. Did their sons and daughters ever chase the desert dust devil? Were they as awed by the spectacle as my young brood?

"It's dissipating!" Craig's booming voice jolted me back to reality.

"You mean dissipating," laughed Grant and Keith, as the sleek-looking funnel gracefully lifted from the ground and dissolved into the milky atmosphere. Even before its last telltale traces had vanished, however, the great vortex was replaced by a group of smaller funnels that seemed to revolve about a common center. These were more the boys' size; and they happily galloped after them to release their balloons.

Just how are dust devils formed? Grant's protestations of exhuberant boyhood notwithstanding, conventional wisdom has it that they are born in thermal updrafts resulting from the intense heating of the earth's surface by the rays of the sun. So they are most common over dry surfaces that can be raised to very high temperatures, and, of course, most visible over ground having a good supply of fine loose particles that can be swept into the air.

As the sun climbs in the sky each day, heating anew the barren ground, a layer of very warm and unstable air begins to form near the surface of the soil. Being lighter than the cooler air above it, this layer has a tendency to rise. However, it cannot rise all at once in an intact sheet; so discreet "bubbles" of this warm air begin to waft upward as the thermals so familiar to sailplane pilots and birds of prey.

When the rate of ascent of these thermals surpasses some critical velocity, the inrush of air (to replace that which is transported upward) takes on a rotary motion, much like the swirling water that exits in a bathtub once the stopper is pulled. This influx of additional low-level warm air further fuels the developing spiral wind field; and, as it rushes upward in the small crosssectional area of the young vortex, its rotational speed is increased in much the same way a figure skater increases her rotation rate when she pulls in her arms and legs to a contracted central position.

Although most people think of dust devils as rather innocuous, such is not always the case. Indeed, one of the world's foremost authorities on vortex wind phenomena, Professor T. Theodore Fujita of the University of Chicago, has written that a strong dust devil is generally more powerful than over one-fourth of all the tornadoes that occur in the world. So it is not unusual to turn on the radio and hear of a house trailer being overturned by a dust devil, or to pick up a newspaper and read of minor structural damage done to houses and farm buildings by these whirlwinds.

Most cases of severe damage, however, occurred in earlier days. The old handwritten weather records of Phoenix, for instance, record that on 29 May 1902 a dust devil "demolished a livery stable, throwing outward the walls on the northeast corner, and carrying the whole roof some distance from the stable, while various debris were found carried several hundred feet away." On the very next day it was also recorded that a dust devil of destructive violence "unroofed the store of H. A. Diehl, near the corner of Washington and Center streets at 2 p.m." Even as late as 1964 a large dust devil destroyed a church that was under construction in Tucson.

In addition to sometimes rivaling tornadoes in intensity, dust devils often mimic them in other ways. The most important of these similarities has to do with the common existence of small but very intense "mini-funnels" within the basic vortex of each type of whirlwind. Scientists believe that these small subsidiary swirls are the cause of most of the damage wrought by tornadoes, and that they are the explanation for the common observance that many times a tornado will completely demolish a house but leave almost unscathed the residence next door to it. It is thought that this peculiar type of behavior is due to the small size "suction vortices," as the mini-funnels are called, that may exist for only a matter of seconds yet do considerable localized damage. Tornadoes generally are believed to have only about three suction vortices in simultaneous existtence. However, I have observed as many as 12 to 16 little funnels churning about the outer periphery of a large 200-yard-diameter dust devil.Dust devils and tornadoes also exhibit similarities when they dissipate. Oftentimes their funnels become stretched into very long, narrow, and contorted structures, called, in the case of the tornado a "rope cloud." I have observed dust devils at this stage of their life that extended a full thousand feet into the air and yet were no wider across than the shoulders of one of my

Devil Wind

sons. Indeed, my sons have often charged into such dust devils and greatly hastened their demise. In the case of larger dust devils, more drastic measures are required. It is reported that a dust devil once formed over a railroad embankment that was under construction and removed about a cubic yard of sand per hour from it for four hours. Its erosive action could not be stopped until a bulldozer was finally driven into it!

In addition to small boys and the hot desert sun, the Arizona Apaches can be counted on as being equally adept at creating dust devils and rather unusual ones at that. They deliberately created them in times past by setting fire to the spines of large cacti. Even today huge whirlwinds are often set in motion by many of the local Indians when they burn stubble on their fields after a harvest. I have observed vortices of such an origin that have stretched a full mile into the sky and were as wide across as a football field.

But what about that most intriguing of situations Ventana Cave? Why has it to this day continued to spew forth little dust devils from its mouth? And what about the legend of the ironwood fire? Was there really a "hexed" region, where a fire would set up a whirlwind that would "blow your head off," as the Indians claimed?

To find out, I contacted Julian D. Hayden who directed much of the actual digging at the cave during the mid-1930s. He essentially confirmed what was contained in the Papago legend, noting that when he and his men would begin work, "tiny whirls of dust would start up in the rear of the cave, increase in size as they approached the mouth of the cave, and by the time they reached the top of the talus, they were powerful enough to take our wheelbarrows and planking with them." He further said that they could watch them for miles in their progress across the desert to the east, "rising to several hundred feet in height."

In the published record of the excavations at Ventana Cave, the University of Arizona's E. W. Haury, leader of the expedition, gives additional support for the legend and some further insights into possible explanations. He

Up . . . . Up . . . . And away! A dust devil forms on the desert floor, crosses a road, then leaps into the air. Generally more powerful than one-fourth of all the tornadoes that occur in the world, the mini-funnels are capable of considerable damage. Sherwood Idso too observed the air currents that moved through the cave, and mentioned that a fire in the wrong spot, especially a hot ironwood fire, “might easily set up a draft to give the story a basis.” In mapping the distribution of wood ash in the cave, Dr. Haury also noted that one area about two yards square was found to be practically ash free, whereas nearby, just outside the “hexed” region, ash was abundant.And so the legend was de-mystified, and at the same time reestablished. But will I ever explain the nuts and bolts of it to my children? I think not; for as I was preparing this article, one of my younger sons came to me, begging for a bedtime story. Having long ago run out of fresh material, I began to relate the tale of Hewultki to him, much as I imagine Papago fathers did to their children long ago. His eyes sparkled and he quivered with delight, as I recounted each little detail. Afterward, he hugged me tightly and tucked his blanket up close under his chin. I know what he will dream tonight; and I know what we will surely seek this summer. The dust devil - that denizen of the desert holds an unfathomable fascination for the human mind. Though they may unravel many of its stillhidden secrets long after my time, I hope that my children will never fully comprehend all that there is to know about this marvelous whirlwind. It is too great an inspiration to be reduced to a set of cold equations and numbers. Long live Hewultki!

Editor's note: Sherwood B. Idso holds a Ph.D in Physics and is associated with the U.S. Water Conservation Laboratory in Phoenix. His interest in dust devils was sparked several years ago by the arrival of a tornado in the MesaTempe area east of Phoenix. Pursuit of his investigation later led to the publication of seven articles in major national and international scientific journals. As a result of his work, both the Center for Atmospheric Research and the Marshall Space Flight Center have begun studies of these unique denizens of the desert.

Bookshelf

by Mary Lu Moore Inquiries about any of these titles should be directed to the book publisher not ARIZONA HIGHWAYS. Book prices listed do not include postage costs.

R. C. Gorman; the Lithographs. By Doris Monthan, with a Foreword by Jules Heller. Northland Press, Box N, Flagstaff, AZ 86002. 1978. 170 р. $35.00.

One of the most talented, multifaceted, personable artists of today is R. C. Gorman. Identifying early his intellectual and artistical gifts, his parents and teachers encouraged his schooling and self-fulfillment. The result was an engaging, good humored young man with boundless energy, whose paintings were soon in demand. A trip to Mexico introduced to him the work of better known artists there and to the medium of lithography. Soon mastering this art form, which takes great patience, skill and painstaking care, Gorman has continued to create prolifically, concentrating on themes recurrent in his other work: mostly Indian, many depicting his Navajo heritage and his respect for women.

Doris Monthan has compiled a catalogue of Gorman's lithographs, organized chronologically, with introductory remarks and important documentation for each work. Her biography of the artist covers all periods of his life and emphasizes people and events which influenced his style, his education and travels, and his continually evolving ideas and exploration of media. Jules Heller's light-hearted foreword acquaints readers with the world of lithography. Also included are brief notes, an index, references and a bibliography which encompasses all items published regarding Gorman, as well as his honors, awards and shows. We recommend this lithographical-biographical summation of a southwestern artist of Navajo heritage whose highly esteemed productions are now a part of the mainstream of American art.

Classified Bibliography of Native Plants of Arizona. By Ervin M. Schmutz. University of Arizona Press, Box 3398, Tucson, AZ 85722. 160 р. $12.00, hard cover; $6.50, soft cover.

A dozen years ago this publication started out as a simple accumulation of references on Arizona vegetation. It grew and grew until there were 3,000 entries in thirty well defined categories. Citations include all types of published and unpublished literature which date from 1838 through 1976 and deal with ecology, distribution, composition and related aspects of Arizona plant species. Careful cross-referencing helps the researcher locate items listed in more than one category. Of additional aid are an index primarily of authors, and paragraphs heading each category which define the contents. For anyone with interests in Arizona flora past and present, this bibliography is a must.

Design and the Desert Environment: Landscape Architecture in the American Southwest. By James D. Miller. Foreword by Patricia Paylore. Office of Arid Lands Studies, University of Arizona, 845 North Park Avenue, Tucson, Arizona 85719. 1978. 216 р. $12.50, soft cover.

"We all know what a desert is . . . don't we?" the author inquires rhetorically. Subsequently, he provides us with concise definitions of deserts, their global distributions and causes. He focuses upon our southwestern deserts and discusses their climates and landforms. Because human beings find it increasingly attractive to live in the desert, architecture must conform to their needs and to constraints of arid environments. Miller points out the strong influences of solar radiation (sun), wind, moisture and vegetation on desert climates, then proceeds to offer ideas on how to utilize shade, terrain and plants to maximize desert landscaping benefits. Use of trees and shrubs for engineering and architectural purposes can yield great dividends, such as controlling erosion and noise, conserving moisture and providing shade and privacy.

To support his suggestions, the author presents several sections of data. Plants useful for landscaping are listed by size and function. A "Plant Matrix" for trees, shrubs and sub-shrubs gives common and botanical names, preferred desert zones, water requirements, physical dimensions and descriptive remarks. Illustrations of various species are keyed to the matrix. Also worthy of note are references, author and subject indexes, a copy of Arizona's native plant law and a sophisticated, comprehensive, computerized, annotated bibliography drawn from the Arid Lands Information System data bank.

This worthwhile contribution is, according to the author, "a source book, or an idea book, on arid environmental design concepts that can be used by professionals and non-professionals alike." We would add and emphasize that in an era of increasing demand for and costs of water and of decreasing supply of this commodity in desert regions, this publication (Arid Lands Resource Information Paper No. 13) could well become a practical guide for future landscaping for a multitude of conservational purposes.

Mexican Folk Tales. Translated and edited by Anthony John Campos. University of Arizona Press, Tucson, Arizona 85722. 1977. 136 р. $8.50.

Anthony Campos grew up in southern California hearing rich, charming tales from Jalisco, Mexico, origin of his family. Recounted by his godmother in their rural Jaliscan background, these folk tales were an integral part of his family's education and tradition. Familiar Hispanic figures such as San Antonio, El Santo Niño (the Child Jesus), the Devil, Spanish counterparts of pixies, and farm animals, are entwined in the plots, which usually point up a moral. Campos has preserved for us in English these delightful, colorful stories, illustrated by the animated drawings of Mark Sanders. A brief foreword by folklorist Jay Martin sets the stage by introducing earlier Spanish and Mexican folklore. General readers and folklorists alike will enjoy these episodes, which have now become part of the heritage of our Southwest.

Navajo Sandpainting Art. By Eugene B. Joe and Mark Bahti. Treasure Chest Publications, Inc., P.O. Box 5250, Тисson, AZ 85703. 1978. 32 p. $4.95.

Navajo sandpainting is a sacred art which accompanies the sacred science of healing. Its intricate execution demands great knowledge, skill and reverence for traditions. Non-traditional usage of sandpaintings in weaving, painting, photography and other art forms was first viewed by many Navajo people with dismay and is still a matter of controversy. In a format and approach reminiscent of his father (Tom), Mark Bahti and Eugene Joe have undertaken to explain briefly in a personal, respectful manner the history and technology of the sandpainting art and then to interpret some of its more prominent subjects. Ably illustrated by Joe and photographed by Oscar T. Branson, the examples, with certain sacred details changed or omitted, portray several of the more important concepts in Navajo mythology. For an introduction to a major facet of Navajo lifeway, this sympathetic treatment will serve well.