Canadian soldiers were arriving Tuesday to battle raging wildfires on the country's west coast, where about 13,000 people have been evacuated in recent days. The smoke has triggered air quality warnings across the U.S. West and Midwest.

Premier Brad Wall said it is the biggest evacuation effort in Saskatchewan's history. About 1,000 military personnel were arriving from Manitoba and Alberta, said Colin King, deputy commissioner of operations with Saskatchewan's emergency management department.

King called the fire situation 'critical,' adding that people evacuated from more than 50 communities won't be returning soon. More than 110 fires are burning in Saskatchewan alone, AP reported.

Environment Canada has issued air quality warnings for much of Saskatchewan and parts of Manitoba, Alberta, and British Columbia, where heavy smoke is visible over Canada's Pacific coast.

Smoke from the wildfires has also led to air quality advisories in parts of the Midwest and western U.S. including Washington, North and South Dakota, Minnesota, Colorado and Wisconsin.