Kjersten Marta Hellem or Peterson

I've been sorting through many many records, and thanks to people at this site and others in North Dakota and Minnesota, have found this for my great grandmother: She was born on 29 Jul 1858, in Verdal, Nord-Trøndelag. She was known as Kjersten Pedersdatter (age 8) on the 1865 census. She left Inderoy, Nord-Trøndelag, from Trondheim harbor on 20 April 1881. (She is named "Kjersten Hellem" here). Her destination was Windom, Minnesota. She married Olaus Austad on 4 April 1882 in Des Moines Twp., Minnesota (on this record, she is named "Kjersti Peterson"), and they shortly after went to Enderlin, North Dakota. I also don't know if Olaus accompanied her - there is someone mentioned as "Olaus Ol "Aarstad" on the same page of the Digitalarkivet. My problem: I cannot find her actual arrival in the US - I've tried New York and Canadian entries, to no avail. However, I could have missed something. Do you have any suggestions? Thank you! Lucia