THE EARLIEST DOCUMENTED TORNADO IN THE AMERICAS Tlatelolco, August 1521

b y Os c a r Ve l a s c o Fu e n t e s

On the eve of the fall of the so-called Aztec empire a tornado swept around the besieged capital—seemingly a rare omen, except that records document subsequent tornadoes in Mexico City.

he Basin of Mexico, artificially drained since (see Jáuregui Ostos 2000; O’Hara and Metcalfe 1997; the seventeenth century, was originally a closed Therrell et al. 2006). T hydrological basin. The lacustrine plain has At the dawn of the sixteenth century the Basin of an average altitude of 2240 m and is surrounded by Mexico was occupied by a chain of shallow lakes and elevated volcanic ranges (3000–5500 m) on the east, inhabited by Nahuatl-speaking peoples distributed south, and west and by low discontinuous ranges on in dozens of altepetl. Literally meaning “water(s) the north (see, e.g., Sanders 1976). The basin’s high and mountain(s)”, “altepetl” can be understood altitude combines with a tropical location (19.5°N) to as city-state although the equivalence is not exact produce a temperate climate with rainy summers and (Lockhart 2004). Estimations of the total population dry winters. This rain regime seems to have prevailed in the Basin range from 800,000 to 1.2 million people, during the whole historic period despite the relatively with one quarter of them living in the twin altepetl large fluctuations in the total annual precipitation of Tenochtitlan-Tlatelolco (Sanders 1992). These were founded in the first half of the fourteenth century in two small islands in the western side of the central lake, Texcoco. Drought conditions prevailed at that AFFILIATION: Velasco Fuentes—Departamento de time, but the climate soon became wetter and the Oceanografía Física, CICESE, Ensenada, México Corresponding Author: Oscar Velasco Fuentes, Tenochca (or Mexica) and Tlatelolca flourished under Departamento de Oceanografía Física, CICESE, Ensenada, México relatively moist conditions (O’Hara and Metcalfe E-mail: [email protected] 1997). Two centuries of development and draining works transformed the two islands into a single one The abstract for this article can be found in this issue, following the table of contents. of about 6 km in north–south direction and 4 km in DOI:10.11752010BAMS2874.1 east–west direction (see Fig. 1). The Nahuas, like nearly all early civilizations In final form 23 April 2010 ©2010 American Meteorological Society with an economy based on agriculture, were meticu- lous observers of astronomical and meteorological

AMERICAN METEOROLOGICAL SOCIETY november 2010 | 1515 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC phenomena. Their achievements in observing the motion of celestial bodies, though not as impressive as those of the Maya, are well documented (see, e.g., Aveni 2001). The surviving pictorial manuscripts also give ev­idence of a careful register of meteoro- logical phenomena such as rains, winds, and storms (e.g., Therrell et al. 2004). The start and end of the rainy season were milestones in their civic–religious calendar. Indeed, two of the most important deities in the Nahua pantheon were related to meteorological phenomena: Tlaloc (He Who Has Earth) was their god of rain, thunder, and lightning and Quetzalcoatl (Plumed Serpent) their god of wind and eddies (Sahagún et al. 1997). In this respect the Nahuas were in tune with other Mesoamerican civilizations. In the whole region the cult of the Rain God goes back to the earliest of times. Thus, the Maya of Yucatan worshiped him under the name of Chaac, the Mixteca of Oaxaca worshiped him as Dzahui, and the Totonaca of Veracruz as Tajin. The cult of the Wind God, usually represented as

a plumed serpent, was just as widely extended and Fi g . 1. The island occupied by the twin cities Tenochti- deeply rooted: the Maya of Yucatan venerated him as tlan-Tlatelolco at the dawn of the sixteenth century Kukulcan, the Mixteca of Oaxaca as Lord 9 Ehecatl, (dark green area); the Greater Mexico City area at and the Maya of Guatemala as Qucumatz (see, e.g., the present time (light green; the black line indicates Jansen 1997). the actual administrative border of the capital). Red ovals show the approximate location of the tornadoes The Nahuas were well aware of the close relation described in the text. Gray lines are topographic con- that exists between the mountains and the rain in tours with the altitude given in meters. central Mexico: on top of the mountains surrounding the Basin of Mexico the clouds gather and rain is produced. Hence they considered the mountains to 1547 and 1569 by the grammarians, is based on be rain gods, the Tlaloque, attendants of Tlaloc. In native documents and interviews with elders of high consequence, they built temples on top of the major status from three altepetl in the basin (Tenochtitlan, mountains around the basin and conceived of the Tlatelolco, and Tepepolco). The Spanish text was pyramids within the city as ceremonial mountains dictated by Sahagún to his assistants around 1578–79. (Broda 1997). It is sometimes a literal translation and sometimes a The most important source of information about paraphrase of the Nahuatl text. Book XII, the only the Nahuas around the time of the conquest is the one fully devoted to historical matters, is an account Historia General de las Cosas de Nueva España, of the Spanish conquest of Mexico (1519–21). In the also known as the Florentine Codex because the introduction Sahagún explains that this book “was original manuscript is kept at the Biblioteca Medicea written at a time when those who took part in the Laurenziana in Florence, Italy. It is the result of over conquest itself were alive, and those who gave this 30 years of work by Franciscan Friar Bernardino account were important people of good judgement de Sahagún and his team of Nahua assistants: the who are considered certain to have told the entire Spanish–Latin–Nahuatl grammarians Antonio truth.” According to Lockhart (2004), the second half Valeriano, Martín Jacobita, Alonso Vegerano, and of Book XII (chapters 20 to 41) faithfully represents Pedro de San Bue­naventura and the copyists Diego the local view of the events, closely resting on oral Degrado and Mateo Severino (Sahagún 1981). The tradition and probably on pictorial documents too. Florentine Codex, divided into 12 books, is an ency- As for factual accuracy, Book XII is not very different clopedic compilation of texts in Nahu­atl and Spanish from the two major Spanish sources, namely Hernán (Fig. 2) dealing with all aspects of Nahua culture and Cortés’ (2001) Cartas de Relación to the emperor life, from social structure and religious matters to Charles V and Bernal Díaz del Castillo’s (1963) Histo- natural history. The Nahuatl text, written between ria Verdadera de la Conquista de la Nueva España.

1516 | november 2010 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC Fi g . 2. Two pages of the Florentine Codex (Florence, Biblioteca Medicea Laurenziana, Manuscript Mediceo Palatino 220, 79v, 80r; published under permission of Italy’s Ministero per i Beni e le Attività Culturali; further reproduction by any means is prohibited). Chapter 39 of Book XII describes the tornado of Tlatelolco, in par- allel Spanish and Nahuatl. The relevant passage occupies the last paragraph of folio 79v and the first of folio 80r. A transcription and an English translation of the Nahuatl text appear in Fig. 3; an English translation of the Spanish text appears in Fig. 4.

A chronology of events, consistent with both 1521, when Cortés sent divisions to three altepetl on Nahua and Spanish sources, is briefly sketched the lake shore: Tacuba in the west, Coyoacan in the here. In November 1519 Cortés and his army were southwest, and Iztapalapa in the southeast. After two received peacefully in Tenochtitlan by Montezuma, months of bloody battles Cortés’ army occupied the the Mexica ruler. The Spanish army was forcibly southern part of the island (Tenochtitlan) and the expelled in June 1520 after Pedro de Alvarado, one Mexica took refuge in the northern part (Tlatelolco), of Cortés’ captains, massacred the local population where they and the Tlatelolca resisted for two more during the celebration of Huitzilopochtli, the chief weeks. Finally, the city fell on 13 August 1521. As is god of Tenochtitlan. Cortés spent the following customary, this date is given in the Julian calendar months preparing his return by forging alliances current at the time; in our calendar the date of the with the enemies of the Mexica, conquer­ing the fall is 23 August 1521. altepetl that refused to cooperate with him, and building brigantines for the assault of the island THE TORNADO OF TLATELOLCO. Chapter city. Meanwhile, Tenochtitlan-Tlatelolco endured a 39 of Book XII (Fig. 2) begins with a description of a smallpox epidemic that decimated the local popu- meteorological phe­nomenon observed by the Mexica lation. Since one of the victims was Montezuma’s and Tlatelolca in the final days of the siege. Figure 3 successor, a new ruler was elected to organize the shows a transcription of the relevant passage of the defense: Cuauhtemoc. The siege started in late May Nahuatl text accompanied by the English translation

AMERICAN METEOROLOGICAL SOCIETY november 2010 | 1517 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC of Anderson and Dibble (Sahagún 1965). A clear If we put this together with the other elements understanding of the nature of the phenomenon in the description, the image of a tornado clearly depends on the words highlighted in the Nahuatl appears. For there was a heavy storm with a blazing text: ecamalacotl and ecatepoztli (since the spelling and roaring whirlwind, which emerged as suddenly in the Florentine Codex is not uniform, here we use as it disappeared. Chapter 39 of Book XII goes on the standard spelling of these words). The meaning to expound that there was no fighting on the day of the former word is undisputed: ecamalacotl has the after the storm, and that Tenochtitlan-Tlatelolco roots ehecatl (wind) and malacatl (spindle). Spanish fell on the following day. This sets the date of the translations, starting with Sahagún’s, use any of two tornado as 11 (21) August 1521. As for its path, this synonymous words: torbellino or remolino. English may be partially deduced from the geographical translations, either of Sahagún’s paraphrase or the details given in the Florentine Codex and Sahagún’s Nahuatl text, use “whirlwind.” 1585 revision of Book XII (see Fig. 4). The latter The meaning of ecatepoztli is less certain. In says that the tornado came from the direction of pre-conquest times tepoztli was the Nahuatl word Tepeyacac (Tepeyac), about 5 km north-northeast for copper and, more generally, any workable, of Tlatelolco, and the former says that it circled the nonprecious metal. By extension it was also used to enclosure of the Mexica in Coyonacazco, a quarter designate objects made of metal, particularly copper of Tlatelolco in the northeastern part of the island axes (Lockhart 1992). So, literally, ecatepoztli means (Calnek 1972). “wind-copper” or “wind-axe.” Anderson and Dibble A Spanish document of the early colonial period use “coppery wind” (Sahagún 1965). Lockhart (2004) lends further credibility to the Nahuatl account. A prefers “wind-axe” and explains that “ecatepoztli few years after the fall of Tenochtitlan, the Spanish was some sort of meteorological phenomenon”. In crown ordered the elaboration of a description of the the analysis of a different text Lockhart et al. (2006) land. The work was completed and sent to Spain in went further toward elucidating the connotations 1532. This document is now lost, but some fragments of ecatepoztli: “reference to its rapid motion and survive in Antonio de Herrera y Tordesillas’ Historia appearing out of nowhere point to a tornado, but General de los Hechos de los Castellanos en las Islas i the meaning is not fully established”. Ecamalacotl Tierra Firme del Mar Oceano (Bustamante 2000). As and ecatepoztli appear in parallel in another pas- Herrera recounts events of the year 1531, he presents sage of the Florentine Codex, chapter XIV of Book the following description of the rain in Mexico City: VI. Here Sahagún makes a literal translation of the “it rains in the same season and at the same hours (as Nahuatl text and renders those words as torbellino in the rest of the country), but with a North wind in and tempestad infernal, respectively. Anderson and the afternoons and not in the mornings, and from the Dibble, for their part, translate them as whirlwind morning till the vesper hour the weather is very fair. and severe wind (Sahagún 1970). At the said hour, about a League to the Northward,

Fi g . 3. (left) Transcription of the Nahuatl text describing the tornado of Tlatelolco. (right) English translation by Arthur J. O. Anderson and Charles E. Dibble (Sahagún 1965).

1518 | november 2010 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC over the mountain range of Tepeaquilla (Tepeyac), a tornado formed on the Adriatic Sea near Ancona, a very black cloud gathers, and soon after comes to crossed Italy, and entered the Mediterranean Sea near Mexico with mighty airflow and whirlwind. Thus Pisa. In his Istorie Fiorentine, first published in 1532, in order to see if it will rain it is enough to look for Machiavelli described the phenomenon as follows: heavy clouds over the mountain range of Tepeaquilla, “This whirlwind, driven by superior forces, whether because then it is certain there will be rain” (Herrera they were natural or supernatural, broke on itself y Tordesillas 1601, fourth decade, ninth book, sixth and fought within itself; and the shattered clouds, chapter). In view of this account we may conclude that now rising towards the sky, now descending towards the storm and tornado that occurred just before the the earth, crashed together; and then they moved in fall of Tenochtitlan-Tlatelolco was not an exceptional circles with very great velocity and stirred up ahead event but an ordinary one occurring at an exceptional of them a wind violent beyond all measure; and in the moment. battling between them appeared frequent blazes and the most brilliant flares” (Machiavelli 1990, p. 270). EARLY EUROPEAN DESCRIPTIONS OF On June 1749 a tornado formed on the western TORNADOES AND WATERSPOUTS. Some coast of Italy, moved inland, and passed over Rome. scholars interpret the tornado of Tlatelolco as being Boscovich (1749) wrote a detailed account including a superstitious construct arising from a desperate a census of the damage in Rome, a review of similar situation. According to this view, the Mexica consid- events reported in the literature, and a discussion of ered the event as a “sign of celestial wrath” (Prescott theories about tornadoes and waterspouts proposed 1873), a “miraculous tempest excited by their gods” by naturalists of all ages. On the basis of eyewitness (Brasseur de Bourbourg 1859), or the “final omen accounts Boscovich wrote that the tornado “appeared that presaged the imminent destruction of the Aztec as a long, dark cloud that went constantly inflaming capital” (León-Portilla 1992). We should notice, how- itself and throwing abundant flares in all directions” ever, that the Florentine Codex contains no explicit (Boscovich 1749, p. 9). mention of the meaning or the cause of this particular Let us now briefly touch upon two texts that give a event. The language used in the description is vivid fairly accurate description of waterspouts and torna- but factual: the noise and the revolving motion are does in spite of the providential interpretation which but defining characteristics of a tornado; as for the underlies them. These examples have the additional fire, it may seem strange now but at that time even interest of being among the earliest European ob- educated Europeans invoked this image to describe servations of these vortices in the Americas. During tornadoes accompanied by lightning. Two well- his fourth and last voyage to America, Columbus known accounts, the first one written around the encountered a waterspout while exploring the coast time of the fall of Tenochtitlan and the second one of Central America. His son Fernando, a 14-year-old two centuries later, exemplify this. In August 1456 member of the crew, later described the episode in the

Fi g . 4. (left) Sahagún’s paraphrasic version of 1579 translated into English by Howard F. Cline (Lockhart 2004). (right) Sahagún’s 1585 revision translated into English by Howard F. Cline (Sahagún 1989).

AMERICAN METEOROLOGICAL SOCIETY november 2010 | 1519 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC following terms (Columbus 1992): “Besides these dif- unpublished manuscript); here we limit ourselves ferent terrors, there befell one no less dangerous and to presenting written and pictorial evidences of wonderful, a waterspout that on Tuesday, December tornadoes in Mexico City during the eighteenth and 13th, passed between two ships. Had the sailors nineteenth centuries. not dissolved it by reciting the Gospel according to Antonio Alzate Ramírez, a reputed botanist and St. John, it would surely have swamped anything it zoologist, was also a careful observer of astronomi- struck; for it raises the water up to the clouds in a cal and meteorological phenomena. His thrice-daily column thicker than a water butt, twisting it about observations of pressure and temperature in Mexico like a whirlwind.” On July 1680 a tornado passed City for the period April–December 1769 were the through Cambridge (Massachusetts), tearing down first systematic series of meteorological data ever many trees and killing one person. Reverend Increase published in Mexico. The following is a brief report Mather, who would later become president of Harvard of a tornado (Alzate Ramírez 1831, vol. 4, p. 389): “On College, wrote an account of the event based on testi- 25 August 1786, at quarter past two in the afternoon, a monies of eyewitnesses and published it in his Essay hose, spout or serpent formed to the north-northwest for the Recording of Illustrious Providences. In other of this capital. It presented itself for seven minutes words, Mather considered this “strange whirl-wind” either in spiral shape or perpendicular to the hori- to be of divine origin (Mather 1856, see preface and zon. Initially it was dark and later it was whitish.” chapter X). A few years later he wrote that “spouts, typhons, or water serpents, as they are called here, occur very TORNADOES IN MEXICO CITY. A tornado frequently in this valley: I have seen once, in the event in what it is now the downtown of Mexico City month of October, the formation of three at the same may surprise the modern reader. Indeed, the current time, two to the south and one to the east. ( . . . ) In view of the scientific community is that tornadoes the present year (1791) a lot of them have formed at a are exceptional events in Mexico. They are thought short distance to the Southward of the city.” (Alzate to occur only in the northeastern states and along the Ramírez 1831, vol. 2, p. 282). coastline of the Gulf of Mexico (Goliger and Milford José Gómez de la Cortina, an eminent philolo- 1998; Berz et al. 2001). An ongoing investigation of gist and politician with a keen interest in geography documentary sources reveals, however, a different and geology, was the founding president of Mexico’s picture. Reviewing books, newspapers, professional National Institute (now Society) of Geography and journals, and governmental bulletins, we have found Statistics. On July 1848 he witnessed a multiple- records of over 180 tornadoes countrywide in the vortex tornado from his house in Tacubaya. At the period 1521–2010. Many more undoubtedly remain time this was a small town outside Mexico City; now to be found in the published literature and also in it is a populous quarter in the western side of the the rich and varied sources of original, unpublished capital (see Fig. 1). Gómez de la Cortina (1995) wrote documents yet to be examined for tornado cases. that early in the afternoon a cloud developed to the Twenty-five of the tornadoes identified thus far southeast of Tacubaya; then, “a little before five, the occurred in the Basin of Mexico, starting with the cloud had grown and started to throw lightning and tornado of Tlatelolco discussed here and ending strong thunder.” After a while “the cloud formed, in with two small tornadoes observed in northwestern its middle, an inverted cone of about half a league in Mexico City in April 2008. Furthermore, half of the the base, and two smaller ones towards its southern tornadoes in our cata­logue occurred in a narrow end. ( . . . ) The larger cone as well as the two smaller stripe, 19°–20°N, that crosses the country from the ones bounced up and down, unceasingly stretching Pacific Ocean to the Gulf of Mexico. It is still unclear and squeezing. Their vertices tilted notoriously whether the higher incidence in this region, which towards the northwest, as if they were attracted by overlaps the Trans-Mexican Volcanic Belt, arises from another dense cloud that was fixed in that direc- the physical conditions being favorable for tornado tion. At about five fifteen of the same afternoon, the formation or from the higher population density color of the middle of the cloud and the base of the increasing the chances of tornado sightings. Either hose or pump was almost perfectly black and their way, it is a remarkable statistic because rough ter- ends were dark olive color, which varied in intensity rain is sometimes believed to inhibit the formation according to the bending and twisting made by the of tornadoes (Bosart et al. 2006). A detailed analysis cloud.” Heavy precipitation, including hail stones of this developing catalogue of Mexican tornadoes larger that 25 mm in diameter, ensued as soon as the will be published elsewhere (Velasco Fuentes 2010, tornado decayed.

1520 | november 2010 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC In 1885 Cleofas Almanza, a student at the San scription appears in Book XII of the Florentine Carlos Academy, painted Tempestad en los Llanos de Codex, which is an account of the Spanish conquest Aragón (Fig. 5), which shows a tornado touching down of Mexico written in Nahuatl in the mid-sixteenth at Sierra de Guadalupe in northern Mexico City. The century. According to it, just before the fall of subject was assigned to him by his teacher José María Mexico-Tenochtitlan a heavy storm accompanied Velasco, one of Mexico’s greatest landscape painters by a whirlwind struck the basin. The whirlwind and an active member of the Mexican Society of Nat- hovered for a while above Tlatelolco, Tenochtitlan’s ural History. Velasco lived in Villa de Guadalupe from twin city, before moving to the lake where it disap- 1874 until his death in 1912 and carefully observed peared. Analyzing the account in the context of the storms striking the area (Báez Macías 1998). His Nahua culture and contrasting it with contemporary handwritten notes have been preserved, so we can European descriptions of tornadoes and waterspouts see how closely Almanza’s painting follows Velasco’s shows that the described phenomenon was a tornado. instructions: “In the plains of Hacienda de Aragon a Since this event predates the Cambridge tornado of storm is observed to break. A great spout has formed. A man, carrying his fishing instruments, and his wife, carrying a child on her back, hastily run away. A canoe is abandoned on the bank of the small lake that occupies those paddocks, as the man has no time to take it home. The hills of El Chiquihuite and La Co- rona, which are part of the mountain range of Villa de Guadalupe, are seen in the distance. Great masses of dust are risen almost to the clouds and the trees bend under the mighty impetus of the hurricane” (see Báez Macías 1998). Almanza’s painting, which is now exhibited at the National Museum of Art in Mexico City, beau- tifully shows that torna- does occur in the Basin of Mexico. Furthermore, it shows a tornado in the same area where, three centu- ries earlier, the tornado of Tlatelolco was observed to start (Sahagún 1989).

SUMMARY AND CON- CLUSIONS. We discuss a meteorological phenom- enon that occurred in the Fi g . 5. Tempestad en los llanos de Aragón, oil painting by Cleofas Almanza, Basin of Mexico in August 1885 (©D.R. Museo Nacional de Arte/Instituto Nacional de Bellas Artes y 1521. The only known de- Liter­atura, México)

AMERICAN METEOROLOGICAL SOCIETY november 2010 | 1521 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC 1680 (Mather 1856; Ludlum 1970), the tornado of Calnek, E., 1972: Settlement pattern and Chinampa agri- Tlatelolco represents the earliest tornado on record in culture at Tenochtitlan. Amer. Antiq., 36, 104–115. the Americas. Documentary sources show that severe Columbus, F., 1992: The Life of the Admiral Christopher storms and tornadoes have occurred under the vari- Columbus: by his Son Ferdinand. Rutgers University ous climatological conditions that have prevailed in Press, 400 pp. the Basin of Mexico throughout the last five centuries Cortés, H., 2001: Letters from Mexico. Yale University (Velasco Fuentes 2010, unpublished manuscript). Press, 640 pp. This is particularly significant because this basin Díaz del Castillo, B., 1963: The Conquest of New Spain. is now the seat of one of the most populous cities in Penguin, 416 pp. the world. Even a weak tornado could represent a Goliger, A., and R. Milford, 1998: A review of worldwide serious threat to life and property in such a densely occurrence of tornadoes. J. Wind Eng. Ind. Aerodyn., populated area. 74–76, 111–121. Gómez de la Cortina, J., 1995: Poliantea. UNAM, Acknowledgments. I am grateful to Rita Guevara 216 pp. Alcaraz for bringing to my attention Almanza’s painting Herrera y Tordesillas, A., 1601: Historia General de los and to two anonymous reviewers for their suggestions and Hechos de los Castellanos en las Islas i Tierra Firme comments on an earlier version of this paper. CONACyT del Mar Oceano. Imprenta Real, Vol. 4, 293 pp. (México) supported this work through Grant 90116. Jansen, M., 1997: La serpiente emplumada y el amanecer de la historia. Códices, Caciques y Comunidades, M. Jansen and L. Reyes García, Eds., Asociación de His- REFERENCES toriadores Latinoamericanistas Europeos, 11–63. Alzate Ramírez, J., 1831: Gacetas de Literatura de Jáuregui Ostos, E., 2000: El Clima de la Ciudad de México, Vol. 2, 459 pp, Vol. 4, 446 pp, Hospital de México. UNAM, 131 pp. San Pedro. León-Portilla, M., 1992: The Broken Spears: The Aztec Aveni, A., 2001: Skywatchers. 2nd ed. University of Texas Account of the Conquest of Mexico. Beacon Press, Press, 411 pp. 196 pp. Báez Macías, E., 1998: José María Velasco: Apuntes para Lockhart, J., 1992: The Nahuas After the Conquest: A sus alumnos. Estudios sobre Arte: Sesenta Años del Social and Cultural History of the Indians of Central Instituto de Investigaciones Estéticas, M. Fernández Mexico, Sixteenth Through Eighteenth Centuries. and L. Noelle, Eds., UNAM, México, 329–336. Stanford University Press, 672 pp. Berz, G., and Coauthors, 2001: World map of natural —, 2004: We People Here: Nahuatl Accounts of the hazards—A global view of the distribution and Conquest of Mexico. Wipf and Stock, 335 pp. intensity of significant exposures. Nat. Hazards, 23, —, S. Schroeder, and D. Namala, 2006: Annals of 443–465. His Time: Don Domingo de San Antón Muñón Bosart, L., A. Seimon, K. LaPenta, and D. Dickinson, Chimalpahin Cuauhtlehuanitzin. Stanford University 2006: Supercell tornadogenesis over complex terrain: Press, 329 pp. The Great Barrington, Massachusetts, tornado on Ludlum, D., 1970: Early American Tornadoes 1586–1870. 29 May 1995. Wea. Forecasting, 21, 897–922. American Meteorological Society, 219 pp. Boscovich, R., 1749: Sopra il Turbine che la Notte tra gli Machiavelli, N., 1990: Florentine Histories. Princeton 11 e 12 Giugno del 1749 Danneggiò una Gran Parte di University Press, 416 pp. Roma. Niccolò e Marco Pagliarini, 282 pp. Mather, I., 1856: Remarkable Providences illustrative Brasseur de Bourbourg, C., 1859: Histoire des Nations of the earlier days of American coloni­sation. John Civilisées du Mexique, et de l’Amerique Centrale. Russell Smith, 262 pp. Vol. 4. Arthus Bertrand, 851 pp. O’Hara, S., and S. Metcalfe, 1997: The climate of Mexico Broda, J., 1997: El culto Mexica de los cerros de la since the Aztec period. Quat. Int., 43–44, 25–31. Cuenca de México: Apuntes para la discusión sobre Prescott, W., 1873: History of the Conquest of Mexico, graniceros. Graniceros: Cosmovisión y Meteorología Vol. 3. J. B. Lippincott, 522 pp. Indígenas de Mesoamérica, B. Albores Zárate and J. Sahagún, B. d., 1965: Florentine Codex. Book 12: The con- Broda, Eds., UNAM, México, 49–90. quest of Mexico. University of Utah Press, 122 pp. Bustamante, J., 2000: El conocimiento como necesi- —, 1970: Florentine Codex. Book 6: Rhetoric and Moral dad de estado: Las encuestas oficiales sobre Nueva Philosophy. University of Utah Press, 260 pp. España durante el reinado de Carlos V. Rev. Indias, —, 1981: Florentine Codex. Book 2: The ceremonies. 60, 33–55. University of Utah Press, 247 pp.

1522 | november 2010 Unauthenticated | Downloaded 10/10/21 10:57 PM UTC —, 1989: Conquest of New Spain: 1585 Revision. University of Utah Press, 672 pp. —, T. Sullivan, and H. Nicholson, 1997: Primeros Memoriales: Paleography of Nahuatl Text and Eng- lish Translation. University of Oklahoma Press, 334 pp. Sanders, W., 1976: The natural environment of the Basin of Mexico. The Valley of Mexico: Studies in Pre-Hispanic Ecology and Society, E. Wolf, Ed., Uni- versity of New Mexico Press, Albuquerque, 59–67. —, 1992: The population of the central Mexican symbiotic region, the Basin of Mexico, and the Teotihuacan Valley in the sixteenth century. The Native Population of the Americas in 1492, W. Denevan, Ed., University of Wisconsin Press, 85–150. Therrell, M., D. Stahle, and R. Acuña Soto, 2004: Aztec draught and the “curse of one-rabbit.” Bull. Amer. Meteor. Soc., 85, 1263–1272. —, —, J. Villanueva Diaz, E. Cornejo Oviedo, and M. Cleaveland, 2006: Tree-ring reconstructed maize yield in central Mexico: 1474–2001. Climatic Change, 74, 493–504.

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