It’s a busy day in the world of news. Here are five need-to-know stories to help you get out the door: Britain is expected to formally file for divorce from the European Union; hernia surgery patients join a lawsuit against the maker of a now-recalled surgical mesh; the UN declares the world's largest humanitarian crisis in seven decades; an embattled Conservative senator comes under fire for arguing that the residential school system had benefits; and Parks Canada documents raise concerns over a proposed trail along the Alberta’s Icefields Parkway.

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1. Making it official: The United Kingdom is set to formally file its withdrawal from the European Union today. Prime Minister Theresa May is expected to invoke Article 50 of the EU’s key treaty, triggering the two-year countdown to Brexit.

2. Class-action suit: Some Canadian hernia surgery patients have launched a class-action lawsuit against the maker of a now-recalled surgical mesh, claiming they weren't warned of its dangers.

3. Humanitarian crisis declared: The world's largest humanitarian crisis in seven decades has been declared in three African countries. Famine has been declared in South Sudan, Somalia and Nigeria.

4. 'A fool of herself': Critics are firing back against an embattled Conservative senator who argued that Canada's notorious residential schools had benefits. Sen. Lynn Beyak, a member of the Senate's standing committee on aboriginal people, says negative stories about the schools overshadowed the good work accomplished at the schools.

5. Unhappy trails? New documents from Parks Canada are raising concerns over a proposed trail along the Icefields Parkway between Banff and Jasper, Alta., from damage to wildlife habitat to safety concerns and increased development pressure.