LOS ANGELES — Local TV newscasts in the 1950s often consisted of five minutes of news, five minutes of sports and another five minutes of weather.

Broadcast journalist Sam Zelman blew up that formula.

In 1961 he created “The Big News” at KNXT-TV (now KCBS-TV) that presented 45 minutes of local news, sports and weather, kicked off by the regal-looking Jerry Dunphy intoning: “From the desert to the sea to all of Southern California, a good evening.”

Local news was never the same, and Zelman, late in his career, went on to help create another breakthrough in TV news that naysayers said would never work – CNN.

Zelman, 100, died Friday at his home in Tucson, Ariz. The cause was respiratory failure, said his wife, Sally Davenport.

Many in broadcasting thought KNXT was crazy to program a 45-minute local news block.

But newspapers, covering a variety of topics, were what Zelman wanted to emulate. “I like the subject to change often,” he told students in Tucson in a 2013 video-recorded class session. “With a newspaper, I can move from one story to another.”

He hired a somewhat hard-bitten group of reporters and editors. They brought with them the stereotypical hard-news lifestyle of the era.

The show had a slow start in ratings, but eventually walloped the competition and was widely emulated across the country.

He had retired when Ted Turner asked him to move to Atlanta in 1979 to help build Cable News Network. One of Zelman’s jobs was to find promising young journalists willing to work for low pay, and some of them went on to become CNN stars.