*In the aftermath of Hurricane Katrina, there were isolated reports of people in neighboring states who saw the influx of displaced New Orleanians into their cities as a burden – or even worse, a nuisance. But imagine if whole cities and states harbored pure hatred and zero sympathy for Katrina survivors – not only making fun of their sudden loss of homes and livelihoods, but developing with ways to keep them as segregated as possible?

Welcome to California during the Dust Bowl, where during the 1930s, white refugees escaping the ravaged Great Plains quickly found out what it was like to live as an African Americans under Jim Crow. [Watch in the promo clip below.]

“There were signs in movie theaters saying, ‘Okies and N words,’ upstairs,” said filmmaker Ken Burns, who chronicles the greatest man-made ecological disaster in American history in his four-hour PBS documentary “The Dust Bowl,” airing 7-9 p.m. Sunday (Part 1) and Monday (Part 2), Nov. 18-19.

Burns calls the Dust Bowl, “a ten-year apocalypse punctuated by hundreds of terrifying black blizzards that killed not only farmers’ crops and cattle, but their children too. All of this was superimposed on the greatest economic catastrophe in the history of the world, the Depression. It was an epic of human pain and suffering, but it is also the story of heroic perseverance.”

The worst of these storms took place on Black Sunday, April 14th, 1935, just halfway through the decade-long cataclysm. It was the final straw for many residents, who realized they had to leave the Southern Plains and relocate to what they thought would be easier times in California.

However, the West coast was not so gracious. California officials quickly erected shantytowns in the Central Valley to house Dust Bowl refugees fleeing the panhandles of Oklahoma and Texas, and parts of southeastern Colorado, northwestern Kansas, and northeastern New Mexico.

“These were unwelcome job stealers,” Burns said of California’s attitude. “So the jungles that were set up in the Central Valley were squalid slums of folks who wanted to pick at harvest season and just hopefully, miraculously disappear, and all were called, wherever they were from, Okies. So the Okies in California were second class citizens.”

(L-R) Author, The Dust Bowl Dayton Duncan, Dust Bowl survivor Cal Crabill, author and columnist Tim Egan, and Filmmaker Ken Burns speak onstage at “The Dust Bowl, A Film by Ken Burns” panel during day 2 of the PBS portion of the 2012 Summer TCA Tour held at the Beverly Hilton Hotel on July 22, 2012 in Los Angeles

A must-see for any fan of Ken Burns films, “The Dust Bowl” not only illustrates with startling detail the grand scale of this disaster, but colors it with intimate, first-hand accounts from the people who witnessed it.

“More than any other film we have made, it is an oral history populated less by historians and experts than those who survived those horrible days,” said Burns. They are at the end of their own lives now, but they were children and teenagers then, their searing memories as raw and direct as if this had all happened yesterday.”

One such survivor, Calvin Crabill, was 11-years-old when he and his father fled Holly, Colorado for Los Angeles. In the film, Crabill talks about the amount of cruelty they suffered after arriving in California. Below, he describes how the animosity was still palpable at his recent 55th high school reunion.

Watch Woody Guthrie: Okies on PBS. See more from The Dust Bowl.