The entire interlobate area is more than 150 miles long. Average annual precipitation ranges from 32 inches in the north to 38 inches in the southwest. Average snowfall ranges from 50 inches in the east to more than 60 inches in the southwest near Lake Michigan.
Many small kettles contain bogs or swamp forest.
Streams are quite numerous on the outwash of Sub-subsection VI.2.1. The largest streams are the Kalamazoo and St. Joseph Rivers. The most common soil textures are sand and sandy loam. Tallgrass prairie was restricted to flat outwash deposits, especially where streams or wetlands did not provide fire barriers. Oak forest was also common throughout, especially in the more dissected ice-contact topography and on the steep end moraine to the north.