BOISE, Idaho (AP) — Australian and New Zealand firefighters have arrived in the United States and on Monday prepared to fan out to help fight wildfires burning in several western states.

The 70 firefighters are scheduled to receive protective equipment at the National Interagency Fire Center in Boise, Idaho, where an air quality alert is in effect due to smoke from regional wildfires.

The firefighters are intended to fill a shortage of mid-level fire managers and include equipment bosses, strike team leaders and division supervisors who will bolster some 32,000 firefighters already in the field.

The U.S. is in the midst of one of its worst fire seasons on record with some 11,600 square miles scorched so far, the sixth worst going back to 1960 with more fire season left. Thirteen firefighters have died.