Animal welfare groups unite in wake of Hurricane Katrina tragedy

An estimated 1.5 million people fled Louisiana before Hurricane Katrina bore down in 2005. Cars jammed on the New Orleans' Causeway in attempts to escape the Category 3 hurricane barreling toward the city sitting below sea-level. Citizens were told to take what they could and flee.

Amid the chaos leading up to landfall, thousands of pets were left behind in houses that eventually were enveloped in floodwaters from the broken levees. The Federal Emergency Management Agency (FEMA) had no plan in place to assist animals, only humans. Refugee centers were forced to separate pets from families.

The fate of these animals rested on a hodgepodge of animal welfare groups who had little experience working together.

SEE MORE: Special coverage on the 10th anniversary of Hurricane Katrina

Dr. Dick Green, senior director of disaster response for the ASPCA, arrived on the ground quickly after the storm struck and remained there for 47 days.

"We spent the first 20 plus days in relatively deep water. Then when the water started to recede our operations changed. We went from strictly floodwater rescue to a combination of water rescue and land rescue. So our mission changed," he told AOL.com.

Most flood waters subside within a week, allowing rescuers to transition to a land-based rescue, Green says, but Katrina was different.

"Katrina was the longest water-based rescue operation I've ever done. The water just hung around forever," he said.

RELATED: 10 years of recovery in New Orleans

The animal welfare groups also were overwhelmed by the outpouring of support from across the nation. Media coverage of the pets affected by Katrina like the infamous forced separation of a 9-year-old and his little white dog Snowball inspired a grassroots movement to help the animals left behind.

"It was such a heart-wrenching thing," Green said, recalling people from every state coming to help. "They filled up their cars with food and supplies, they drove all over the country and showed up and we didn't know how to put them to use ... We did not know how to manage all of these groups that came to help."

Over 8,500 animals were ultimately taken to the makeshift shelter set up at the Lamar-Dixon Exposition Center in Gonzales, La.

Another estimated 250,000 dogs and cats were displaced or died as a result of Katrina, according to the ASPCA, including an unknown number of other animals such as fish, small mammals and horses.

See the pets, and their owners, who struggled in the aftermath of Katrina:

Thanks to major strides made since 2005, the United States is unlikely to see another disaster affect pets the way Katrina did.

By fall of 2006, President George W. Bush signed the Pets Evacuation and Transportation Standards (PETS) Act into law, making certain that FEMA included plans to help individuals with household pets and service animals in the wake of a catastrophe.

The relationship between all of the animal welfare organizations that banned together has now been formalized.

"Prior to Hurricane Katrina, we were notorious for working independently. We weren't real keen on coming together. Katrina forced us to come together. There was just no way we were going to be able to manage that individually," Dr. Green said.

Dr. Green credits the delegation of authority from the ASPCA and Humane Society of the United States (HSUS) with setting up temporary shelters.

"It brought everyone under that umbrella," he said.

RELATED: The Hurricane Katrina memorial you likely don't know about

About six months after Katrina, the National Animal Rescue and Sheltering Coalition (NARSC) was formed, which includes shelters across the country, PetSmart charity, federal organizations, the American Red Cross and more.

"It is just so cool to see how far we have gotten," Dr. Green said looking out at the NARSC bootcamp and seeing individuals wearing 10 different organization shirts mingling. "We have put our differences aside."

Infographic shows statistics on pet ownership during Katrina:

For more 10th anniversary Hurricane Katrina coverage, click here.