Harry Shearer says his "head exploded" 20 months ago. That's when he heard President Barack Obama, during a town hall meeting in New Orleans, refer to the flooding of the city after Hurricane Katrina as "a natural disaster."

The comedian, actor, radio host and writer, widely known as a co-creator of the mock-documentary "This is Spinal Tap" and a voice actor for "The Simpsons," channeled his outrage into his first real documentary, "The Big Uneasy." This lucid, civilized but merciless expose debunks every myth surrounding the near-ruination of New Orleans in 2005.


Shearer, who divides his time between New Orleans and Los Angeles (and, these days, London), lambastes the accepted media equation that "massive hurricane + city below sea level = natural disaster." With experts like Robert Bea of the University of California, Berkeley and Ivor van Heerden, formerly of Louisiana State University, he makes a waterproof case that the flooding resulted from design and construction faults in four decades of work by the Army Corps of Engineers.

Shearer will introduce the film at the Charles Theatre at 7 p.m. Tuesday and answer questions about it afterward. He spoke with The Baltimore Sun last week while making a similar stop in San Francisco.

This movie starts with a very cool, scary sequence: a computer-animated map depicting the multiple points where New Orleans' defenses against water failed.

I feel that every once in a while, stuff like computer animation should be used for good as opposed to evil. My only regret was that we didn't have the money or the time to do the equivalent of what you saw during the Japanese tsunami, allowing you to imagine that you were in a plane with a camera in it, flying directly overhead — because what you saw during the tsunami was exactly what was described as happening during the flooding of New Orleans.

But in a way, keeping it more abstract signals to the audience that this film is going to be analytical, not just emotional.

I think that everything good or bad about that period, from network coverage on, too often pushed emotional buttons. I asked a network anchor — in public, in New Orleans — why his broadcast's viewers didn't know why the city was flooded. His answer was, literally, "Honestly, we think the emotional stories are more compelling for our audience." That's a verbatim quote. I wanted this film to counterbalance that. I figured if I was going to make any mistakes, I was going to make them in the direction of being informative. What a novel notion for a documentary!

The film is refreshing partly because it's so nonpartisan. The Republican senator David Vitter comes off as a statesman when he demands to know, in a 2009 hearing, why the Army Corps of Engineers has chosen a protection plan for the city that is inferior to a more expensive plan.

Aside from the sheer entertainment value of watching that exchange, I put that in to underline the fact that this is not a partisan issue. The failure to come to grips with the problem before or after it happened — both parties have an oar in that water. People love to focus on "Oh, so-and-so is biased because he's Left, and so-and-so is biased because he's Right." What underlies this story is much more basic and subversive — laziness and money and ego.

One can argue that the reason this story never got covered by the national media is that it's just too difficult and confusing. It was really two different events — a hurricane event in Mississippi and an engineering event in New Orleans. And even as an engineering event in New Orleans, there were at least two different parts of it, involving, on the one hand, three outfall canals, and, on the other, "Mr. Go" [the Mississippi River Gulf Outlet]. You can imagine an editor in New York dozing off halfway through.

You maintain an even tone with everyone. There's nothing Michael Moore about this movie.

That came from two things. I grew up watching traditional television documentaries like "CBS Reports"— I know it sounds wacky to the kids, but 40 or 50 years ago, television really did these things! And since I was a guy coming from so left-field a place — not just from comedy, but from mock-documentaries — I felt I couldn't afford to stack the deck in any way, or to steal the camera from the participants, or to lard it with music to make you feel what I wanted you to feel, subliminally. I really had to play it as straight as possible if I wanted it to work at all.

Before Hurricane Katrina, were you aware of the potential for disaster?

I first went to New Orleans for the 1988 New Orleans Jazz and Heritage Festival. I had been doing a film as an actor in Seattle and I had the weekend off; some friends asked me to go and join them. I was there for all of a day and three quarters, and that was enough for me to fall in love with it. I went to New Orleans for all the delights of the place. The city itself was not an invitation to take a post-graduate engineering course.

There were reassurances all around. There were warnings in the local paper of what would happen if a Category 5 hurricane directly hit the city. But most hurricanes don't directly hit the city — even Katrina followed the historical pattern of veering off to the right and directly hitting Mississippi instead. So that went into the same part of my mind as all the warnings you hear in Los Angeles of what would happen if the big earthquake hits. But when you actually went through the disaster and learned that it wasn't even the one they had predicted, that it was something else … well, given the fact that my house wasn't damaged, I had the time and energy to learn about what happened.


What do you and your New Orleans friends think about the HBO-series "Treme"?

When HBO announced renewal of "Treme" for a second season, it was above the fold on the front page of the Times-Picayune. A lot of movies get shot there; it's no longer a novelty to have jobs provided by a visiting production. And there've been so many horrible incarnations — do you remember that short-lived Fox police show, "K-Ville"? That sticks out like a sore thumb. It was set in post-Katrina New Orleans, and it gave rise to that utterly mythical, utterly risible cliche, "Let's go to a gumbo party." I think there's a great feeling that despite any faults — and it has some — no one has ever gotten or will ever get as close to a true fictional depiction of New Orleans as "Treme."