Among the most compelling images coming from the Hurricane Harvey aftermath are volunteers and first-responders leading and even carrying strangers, fellow citizens through the historic flood to safety. Many of the rescued clutch beloved pets.

But there are other compelling images of pets abandoned or separated from families, sitting hungry on swamped cars surrounded by miles of water, even swimming aimlessly in the vast muddy waters looking for somewhere to rest.

In Hurricane Katrina 12 years ago an estimated 600,000 pets and livestock were lost in the winds and flooding. Thousands of pets have already been lost in the latest Texas flood. Shelters as far away as California, Maryland, Minnesota and Oregon are preparing for a flood of foster or possibly even permanent guests.

“People love their animals,” said one volunteer staging for the new arrivals. “It’s heartbreaking.”

The Pets Alive Shelter in Austin has been a kind of independent command center for animal rescues in the afflicted areas to the south. That shelter alone is expecting to house more than 1,000 animals by the end of this week.

To make room for an anticipated influx of flood pets, Wings of Rescue, an emergency mercy flight operation, has already transported more than 100 dogs and cats from Louisiana animal shelters to San Diego, where they’ll be distributed to a number of area rescue facilities and available for immediate adoption.

“When disasters strike and the country needs help caring for lost, strayed or abandoned pets,” said John Van Zante of the Rancho Coastal Humane Society, “they turn to San Diego.”

Operation Bring Animals Home is sending volunteers including Dana Deutsch from suburban Chicago to Texas from as far away as Chicago to help rescue lost cats and dogs. “Disaster response is my passion,” says Deutsch, who spent months in Louisiana coaxing terrified dogs and cats from the debris and collapsed homes after Katrina.

The SPCA of Texas says it was overwhelmed with volunteers and potential foster families eager to help but could still use donations here.

Other organizations are also mobilizing for the flood of flood-stricken pets including the Humane Society of the United States, GreaterGood.org, Wings of Rescue and the American Society for the Prevention of Cruelty to Animals.