Convoys of trucks loaded with relief supplies have streamed toward Houston since Hurricane Harvey slammed the Texas coast on Aug. 17. But close observers might have noticed that at least one truck arrived in the city empty. Though it was also part of the relief effort, that particular truck had a different type of mission—hauling some sensitive cargo out of the storm-wracked zone.

In the aftermath of the flooding, drivers for the Pittsburgh Aviation Animal Rescue Team (PAART) drove south from their base at Pennsylvania's Allegheny County Airport to pick up dozens of dogs that have been displaced or left unclaimed after the storm. They then hauled their canine cargo to a waiting animal shelter in San Antonio.

Though the rescue effort presented logistical challenges, "it's great to be able to help out," PAART Executive Director Mary Withrow said in an interview. "I've worked with a bunch of hurricanes. It's so emotional," she said. "Sometimes, you see [people] who find new shelter but they're not allowed to [bring] their pets. There's so much loss and sadness. But there can be happiness, too, when pets are reunited with their families."

PAART hauls displaced pets around the country using two small airplanes and a modified trailer that can hold up to 43 dogs in crates mounted along the walls, keeping the animals calm with soothing music, lavender oils, and running water. Meanwhile, their colleagues work the phones in a race to find space for the animals in nearby shelters, where they can be housed, photographed, and with luck, reunited with their owners.

That process of balancing supply and demand was "a mess" in the logistical vacuum following Hurricane Katrina in 2005, Withrow said. But rescue groups now coordinate their efforts, so PAART, which operates seven local animal shelters in the Pittsburgh area, can supplement its resources through nationwide programs conducted by the U.S. Federal Emergency Management Agency (FEMA) and Humane Society of the U.S.