Since Pokemon Go was released, trainers have noticed that Lapras spawn have patterns. In the Silph Road, numerous reports were gathered regarding the activities of various Pokemon since the beginning. Redditor valuequest and others have been exchanging ideas about the link between the spawn of Lapras and Snorlax.
Comment threads from the Silph Road are discussing about these. It was noticed that spawns of Lapras are located within the vicinities of cities which are close to huge bodies of water. There are data that support this claim. The spawn can be noticed in coastal states such as New York or Florida. There are however minimal spawns of Lapras in the center and south west states of America. These are according to the researches made by the Silph Road. Some users also said that even if there were a lot of bridges in Colorado River in Austin, they have not found Lapras.
According to Otakukart, one user said that Snorlax is a good fit if we use a population density map - a kind of basis that Niantic use for Pokemon spawning. However, Lapras may not fit in this category. Pokemon Drowzee and Dragonite also have distributions in high latitudes and at elevation.
Additionally, the city of Austin possesses city-wide scanners within the entire city. However, it has not shown any Lapras in its recently scanned areas in its stats page. It can then be concluded that Lapras has not spawned in that particular area. On the contrary, another user said that Lapras has a biome that can be considered rare; therefore it will be hard to find out what it really is. It can be noted that major cities like Santiago do not also have Lapras and Porygon, therefore this is not just a product of random chances.