The two sisters came to Wisconsin with their parents and brothers in 1870. I can find the sisters in the 1880 census, living separatly:
Andrine Svarstad, 12. Living in Rising Sun, Crawford, Wisconsin.
Pernille Svarstad, 20. Living in Sterling, Vernon, Wisconsin.
Their brother Anders supposedly married Mari Davidsdatter Hjelle, but I can't find him.
I'm a distant relative.