1.3+ million Snow Geese in one area? This sounds like a road trip.
Loess Bluffs National Wildlife Refuge (formerly Squaw Creek NWR) is located outside of Mound City in northwestern Missouri. It is well-known for its huge concentrations of Snow Geese during both the fall and spring migrations.
It is an impressive spectacle to see tens of thousands of Snow Geese take wing when a Bald Eagle cruises low over these birds resting on water. You would think there would be a lot of geese injured in this mayhem. But oddly enough, crashes between birds are rare. They are well adept at avoiding collision with neighboring birds.
There are several color variations of Snow Geese. When looking at large flocks, you will notice both white birds and dark birds. Both are Snow Geese. The dark ones are referred to as a blue-morph. And yes, the white and dark birds do inter-breed.
Some estimates put the population of Snow Geese at 16 million birds across our continent.
Waterfowl is on the move. Keep your eye on the sky and look over water bodies for various types of geese and ducks.