OTTAWA • The weather is frigid on the border between the US state of North Dakota and the Canadian province of Manitoba, but a growing flow of asylum seekers keeps coming, hoping for refuge in Canada.

"It's a new underground railroad," said Mr Bashir Khan, an immigration lawyer in Winnipeg, Manitoba, referring to the clandestine network that slaves used in the mid-19th century to escape.

Last weekend, the Royal Canadian Mounted Police reported that it picked up 22 people near the border town of Emerson, after they had walked for as long as four hours in sub-zero temperatures. They were taken to offices of the Canadian Border Services Agency, where they all made refugee claims.

In the past six months alone, Mr Khan said that he has handled at least 30 claims of asylum seekers who sneaked over the border.

Two of his clients, 24-year-old Seidu Mohammed and 35-year-old Razak Lyal, suffered severe frostbite when they got lost in a farmer's field in waist-high snow on Christmas Eve en route to Canada.

Mr Mohammed has lost all of his fingers and Mr Lyal has been left only with his thumbs. The two men, both from Ghana, have asylum hearings scheduled for next month.

Mr Khan said the increased flow of refugees heading north has become acute since the election of United States President Donald Trump, particularly after last month's travel ban was announced.

"Nobody ever comes to Manitoba in the dead of winter. It shows how desperate they are," he said.

"They really are afraid of what's happening in the US," said Ms Rita Chahal, executive director of the Manitoba Inter-faith Immigration Council. "They're concerned about deportations and about not having a fair hearing in the US."

Ms Chahal said that her agency opened 270 new cases in the first nine months of last year, compared with 60 or 70 in a typical year.

The asylum seekers take these risks because of the Safe Third Country agreement between Canada and the US, which means a refugee must make his claim in the country of arrival. If they first land in the US, Canadian authorities will send them back if they try to make a claim at the border.

The agreement presumes that each country is safe for refugees and is aimed at reducing "asylum shopping". But it is enforced only at formal ports of entry like airports. A person who crosses into Canada on foot is free to claim asylum.

With no barriers on the vast prairie, crossing over to Manitoba is relatively simple - in good weather.

WASHINGTON POST