BOISE, Idaho (AP) — Empty cow pastures on one day can be bustling with hundreds of firefighters the next as fire camps with colorful tent cities spring up. More than 20,000 wildland firefighters are battling some 100 large wildfires in the U.S. West, and truckloads of supplies and equipment are needed to keep them effective at fighting flames for weeks on end. The largest blazes can draw more than 1,000 firefighters and support staff. Food caterers, semi-trailers with shower stalls and portable bathrooms are brought in. An incident commander with decades of firefighting experience runs the show, plotting short-term and long-term strategy that’s recalibrated daily.