Statistics Canada says the extensive flooding that hit Alberta in June produced a net loss of 5.1 million hours of work.
The agency says 300,000 employed Albertans, or 13.5 per cent of the total working population, lost 7.5 million hours of work during the floods.
At the same time, 134,000 people, or 6.0 per cent of workers, put in 2.4 million additional hours.
There was a net loss in hours worked in all industries, except utilities and public administration.
More than a quarter of professional, scientific and technical workers missed work in the second half of June, with the number of hours lost totalling 1.4 million.
The natural resources industry also lost 1.4 million hours of work, mostly in oil and gas extraction.