Unhealthy air has invaded Minnesota, Wisconsin and North Dakota early this week as a new round of wildfire smoke from Canada has wafted into the region, choking out areas as far south as Chicago and Detroit.

A fast-moving wildfire near the Grand Canyon’s North Rim has destroyed the historic Grand Canyon Lodge and dozens of other structures, triggered a chlorine gas leak, and forced widespread evacuations.

Wildfire smoke from Canada has made for bad air quality over parts of the Upper Midwest. Most of Minnesota had “unhealthy” air quality Saturday.