Harry Shearer is best known for being funny. He voices Mr. Burns and a host of others on The Simpsons. He was a writer and cast member on Saturday Night Live. He starred in This Is Spinal Tap and A Mighty Wind.

But there is nothing funny about The Big Uneasy, Shearer's documentary about why New Orleans flooded in 2005 in the wake of Hurricane Katrina. The film is showing Saturday in Olympia, along with a Q&A with Shearer via Skype.

The veteran actor, writer and radio host never intended to turn from mockumentaries to documentaries, but after the flooding in New Orleans, where he lives, Shearer felt he had to act.

"This was not a career plan," he says. "This was not something I was looking at doing until literally the moment when I saw President Obama at a town meeting in New Orleans in October 2009 refer to the flooding as a ‘natural disaster.'

"I thought, ‘This is either pandering to or partaking of national ignorance on this subject, and I have to do something to penetrate the miasma of misinformation.'"

As Shearer reports in the documentary, two separate independent investigations found that it was not the hurricane but flaws in the levee system protecting the city that led to the tragedy. He also speaks to a whistleblower with the Army Corps of Engineers.

The role of the levee failures in what happened in New Orleans has been widely reported in the city itself, he says, but the national media has continued to focus on the flood rather than on how the damage could have been prevented.

He hurried to complete the film by August 2010, the fifth anniversary of the hurricane.

"I knew the national media would be back down there," he says. "They'll cover the fifth anniversary of anything." But while the media did flood into New Orleans to cover the anniversary, he says, the coverage didn't include a focus on what had been learned since the tragedy.

"I did not anticipate that they would just pull out the tapes from five years ago," he says.

Shearer has been focusing on touring the country with the film, particularly while The Simpsons is on summer break. Come fall, though, he'll be spending parts of three days a week filming the show, now in its 23rd season. He's also written a musical that might soon be produced in London and did a pilot for a TV series there.

"It's a comedy show about Richard Nixon, and I get to play Nixon," he says. "I'm going back to fun projects."

The Big Uneasy

Saturday, July 30, 6:30 p.m.
$8.50, $5.50 for Olympia Film Society members, $4 for kids
Plus Q&A via Skype with filmmaker/actor Harry Shearer
Capitol Theater, 206 Fifth Ave. SE, Olympia
360.754.6670 or olympiafilmsociety.org