I’ve written a lot here recently about the Athapaskan migration(s) into the Southwest. It’s a very interesting topic in a lot of ways. I find it especially fascinating because although the evidence that it happened is very strong, nothing else about it can be easily determined. We know that at least one migration of Athapaskan-speakers from northern Canada to the Southwest happened, but we don’t know when it happened, what route it took, or why the Athapaskans left the north in the first place. Archaeology, linguistics, and ethnography all contribute some clues to this puzzle, but there’s so much ambiguity remaining that the mystery is by no means anywhere near solved.
In addressing the “why” question specifically, it is perhaps most fruitful to look at the starting point rather than the ending point. Although archaeological evidence for Athapaskan groups in Alaska and Canada doesn’t seem to appear until the early centuries AD, and even then it’s not necessarily entirely clear who those people are, this is much more evidence for Athapaskan presence in a particular place at a particular time than anything in the Southwest until historic times, and infinitely more evidence than anything anywhere in between. Looking at the north also has the advantage of the continuing presence of a wide variety of Athapaskan groups, and their linguistic relationships and oral traditions are potentially useful evidence in understanding their past, and by extension the past of the people who once lived among them but later went south.
A fascinating paper from 1992, though not focused specifically on the migration of the Southwestern Athapaskans, contributes considerably to this issue. The starting point is oral traditions among some, but not all, of the northern Athapaskans describing phenomena at the beginning of time that sound very much like the events surrounding the eruption of a volcano. This isn’t very surprising, since Alaska is an area with considerable volcanism, but it’s important to note that even in volcanically active areas volcanoes don’t actually erupt very often. Indeed, intervals between eruptions are routinely measured in centuries or even millennia. Since human generations are so much shorter, knowledge of volcanic eruptions in oral history, even if, as is usually the case, it’s in a very heavily mythologized and allegorical form, in most cases probably results from direct experience of specific eruptions that can be dated geologically and correlated with the human occupation of the area. A well-known Southwestern example is the eruption of Sunset Crater near Flagstaff, Arizona in the late eleventh century AD. This event remains well-remembered in Hopi traditions, and it has also played a considerable role in the development of archaeological ideas about the Sinagua people who inhabited the area prehistorically.
Turning back to the northern Athapaskans, the only volcano to have erupted in the (rather extensive) areas they have traditionally occupied in the relatively recent past is Mt. Churchill, in eastern Alaska very close to the border with the Yukon Territory. There appear to have been two major eruptions of this volcano: one around AD 20, which resulted in a major area mostly to the north being covered in volcanic ash, and another much larger one around AD 720 which resulted in a very large area to the east being covered with a thick layer of ash. If, as seems probable, Athapaskan-speaking people were living in the area when these eruptions occurred, they would surely have made a profound impact on their lifestyles. Indeed, either or both of them could have made such large areas uninhabitable that the people who had been living there migrated elsewhere. And that, of course, is where the relevance of all this to the Southwestern Athapaskans comes in.
So, assuming the oral traditions of the northern Athapaskans record a memory of an actual volcanic eruption, which one was it? The authors of the article conclude that it was most likely the AD 720 eruption. For one thing, this is the more recent one, and it would be more likely to be remembered simply on that basis. It was also more powerful than the earlier eruption, which would also make it more memorable. Indeed, it was a very powerful eruption. It had a Volcanic Explosivity Index of 6, the same as Krakatoa and Mt. Pinatubo.
There’s also the matter of which specific groups have the traditions in question. It turns out that the volcano traditions are not present among all northern Athapaskan groups, but are highly localized among the peoples of the Mackenzie River region of the Northwest Territories, due east of Mt. Churchill and the ash fall from the AD 720 eruption. Some of these peoples have traditions mentioning a mountain that exploded in fire, while others mention conditions that sound like the ash fall and the subsequent period of cold weather. There are also references to the discovery of copper, which occurs in elemental form in the general area and may have been dislodged by the eruption, around this same time, and some of the stories even link the copper directly to a fiery mountain. In historic times the people who lived in the area of Mt. Churchill controlled a substantial amount of the trade in native copper, which only occurs in a few parts of North America. These groups, however, although they do speak Athapaskan languages, apparently do not have any traditions referring to a volcanic eruption, which suggests that they were living elsewhere at the time and only moved into the area after it had recovered ecologically from the effects of the ash fall. Similarly, a recent study has suggested that the caribou populations in the area today are not related either to surrounding populations or to the caribou that lived in the area before the eruption, suggesting that it was uninhabitable for caribou for some period after the ash fall.
Thus, the article concludes that it is very likely that the AD 720 eruption made the area uninhabitable and so traumatized the inhabitants that they moved to the east, past the mountains into the Mackenzie River valley, to become the various peoples that the article refers to collectively as the “Dene” (something of a confusing term, since most of the Athapaskan-speaking groups call themselves by a cognate of this term, such as Navajo Diné). The traditions also refer to a divergence of languages after the time of the eruption, before which all the people could understand each other. This is certainly intriguing, since this is apparently what did happen, but it’s important to note the similarity to the Tower of Babel story here. These stories were recorded by a Christian missionary who spent many years in the area, and the people he ministered to would certainly have been familiar with the Babel story and may have incorporated parts of it into their own traditional stories. Nevertheless, they may have done so specifically because the story of the eruption already involved a divergence of languages. There is, of course, no volcano in the story of the Tower of Babel, so there’s something more going on here than a straight adaptation of a biblical story to a native context.
The connection to the Southwestern migration is somewhat subtle. Since the Navajos and Apaches don’t have anything like these volcano traditions, it doesn’t seem likely that the eruption forced people to migrate all the way across the continent. Rather, it’s more likely that the migrating Dene from the ash-fall zone entered territory previously occupied by other Athapaskan groups and set off a chain reaction of migrations that eventually led to the Pacific coast and the Southwest. The details and dates remain vague, of course, and will continue to do so until the elusive archaeological evidence for the migration itself appears. If the eruption was the ultimate cause, however, it does set a terminus post quem for the migration, which couldn’t have happened earlier than AD 720 and probably would have been some time later, after the early parts of the chain of population movements had occurred. Note that this doesn’t say anything in particular about when the Athapaskans arrived in the Southwest; pretty much all dates that have been posited so far would work with this scenario. Nor does it give much insight into the route the migration would have taken, which depends on who was living where and which way they went after being pushed out.
All of this evidence points to the era after the breakup of Proto-Athapaskan as the time of the eruption, which makes sense for other reasons as well. The most divergent Athapaskan languages (i.e., the ones likely to have broken off earliest) are to the west, further into Alaska, and they don’t have any volcano traditions. Nevertheless, and more speculatively, the authors suggest that the earlier, smaller eruption of Mt. Churchill might have played a role in the initial breakup of the protolanguage, despite not being impressive enough to be remembered. If the protolanguage was spoken in the area around the volcano, which some have suggested on other grounds, then even a small eruption could have sent some groups away early, resulting in the striking diversity of northern Athapaskan language groups. Some of those people might even have come back and resettled the Mt. Churchill area after the AD 720 eruption. Again, though, this is all speculation without much evidence behind it.
Overall, I think this is a fascinating subject. The interaction between people and the environment gets a lot of attention these days, but it’s mostly in the context of people’s effects on the environment. Sometimes, however, the environment gets to call the shots, and it does so in the form of flaming mountains and showers of ash. People just have to deal with it the best they can.
Moodie, D., Catchpole, A., & Abel, K. (1992). Northern Athapaskan Oral Traditions and the White River Volcano Ethnohistory, 39 (2) DOI: 10.2307/482391