Why are flags at half-staff in Colorado on Sunday?

DENVER (KDVR) -- Colorado Governor Jared Polis ordered flags across the state to be lowered to half-staff Sunday in honor of the National Fallen Firefighters Memorial Service.

The lowering of the flags is also to "pay our respects to the brave firefighters and first responders who risk their lives to protect Coloradans and people across the country," according to a statement.

The flags will stay lowered all day Sunday.

The memorial service takes place annually in Emmitsburg, Maryland.