In association with the great drought, there came forth poisonous serpents also upon the face of the land, and did poison many people. And it came to pass that their flocks began to flee before the poisonous serpents, towards the land southward, which was called by the Nephites Zarahemla. And it came to pass that there were many of them which did perish by the way; nevertheless, there were some which fled into the land southward." (Ether 9:31-32)
In review, the people of Omer were living in the land of Moron (Ether 9:13). By the time of the drought, the general land of Moron had probably absorbed the land of Nehor (Ether 7:3-22), had probably absorbed the land of Heth (Ether 8:2 - 9:13), and probably also had some claim on the land of Ablom by the seashore (Ether 9:3). The people had also built "many mighty cities (Ether 9:23). From this enlarged land, their flocks began to flee southward towards the land called Zarahemla by the Nephites. (Ether 9:31) This was probably the general land of Zarahemla. Though not mentioned specifically in the text, we might presume that this "land of Zarahemla" was somewhat near the land of Moron. Ether 10:19 and 10:21 seem to imply that Moron was probably near enough to the land southward that sufficient game could be brought back without too much loss or spoilage, and that the hunters wouldn't have to travel very far.
With this information in mind, and assuming a Mesoamerican setting, David Palmer postulates that there could not have been large rivers, deserts, or impassable mountain ranges for the flocks to cross. A downhill flight through the valleys of Oaxaca (his proposed land of Moron) to the area of Tehuantepec City (the area of his proposed small neck of land separating the land northward and the land southward) seems within the realm of possibility. [David Palmer, In Search of Cumorah, p. 46]