LISA DESAI:

Much of the four thousand mile American border with Canada is wide open and unsecured. In the first three months of this year, a steady stream of immigrants from all over the world braved the bitter cold to reach a country where they believe there's less risk of detention and deportation.

Just north of Minnesota and North Dakota lies the Canadian province of Manitoba. The town of Emerson is a main entry point. An hour's drive north is the provincial capital, Winnipeg, a city of 700-thousand. That's where I met this woman from Somalia.

For her safety, we agreed to shield her face and call her "Nasra." She settled in Minneapolis on a U.S. medical visa to get treatment for her six-year-old autistic son. Her family is part of a minority clan persecuted in Somalia's civil war.