When War Erupted, L.A. Tuned In Big : Ratings: As 3.7 million households follow the Baghdad battle, CNN conquers the air.

As three CNN reporters described the flashes of lights and tracer bullets lighting up the skies over Baghdad, Los Angeles residents turned to their television sets for news of the war in staggering numbers, according to A. C. Nielsen ratings figures.

At 6 p.m. Tuesday, less than 2 1/2 hours after the initial reports of U.S. bombing of Iraq, about 3.7 million households in the Los Angeles area--nearly 75%--were tuned to one of the myriad TV outlets that interrupted regular programming to offer nonstop coverage of the war.

Less than 100,000 area homes were tuned to anything other than war news at that time.

Early in the evening, the total number of area households watching television was up dramatically from the previous Wednesday, varying from 400,000 to nearly 700,000 additional homes. But as the evening wore into prime-time and with no entertainment programs to be found, the number of sets in use settled in at about their usual levels.

Still, at 8 p.m., about 3.5 million out of the Los Angeles area’s 5 million television households were tuned to war coverage on the three networks, the four independent stations, CNN or the two Spanish-language stations.

By 10 p.m., 3 million homes were still tuned in to some form of war coverage. At 11 p.m., the number had fallen to about 1.9 million homes; by midnight to about 1.6 million. But even that number was up from the previous Wednesday, when only about 1.4 million television sets were in use at midnight.

The big winner in all of these numbers was CNN, which featured the only live coverage, via satellite telephone, of what was going on in Baghdad. Though CNN’s ratings were lower than those of NBC and ABC, the cable network beat CBS in Los Angeles throughout the entire evening, even though it is available in less than 60% of all area homes.

By 9:30 p.m., as the local network-owned stations began airing more of their own coverage, CNN became the most watched program in all of Los Angeles, despite its tremendous disadvantage in the number of homes it can reach.

At 11 p.m., when the network-owned local stations were offering their regular newscasts, 20% of all sets in use were tuned to CNN. It continued as the most-watched outlet until about 11:45 p.m.

CNN’s audience was even wider than that, however, because for much of the afternoon and evening, all four independent stations simply broadcast the CNN feed on their own air. Adding the ratings for those stations to CNN’s means that nearly 1.2 million local homes were watching CNN at 6:30 p.m. and 1.4 million at 8:15 p.m.

On an average night, CNN is generally watched in less than 50,000 local homes during prime time.

The highest rated broadcast network coverage at 8:15 p.m. Wednesday was NBC with just over 600,000 area homes. Even though all three of them reached 100% of all area homes, ABC, CBS and NBC combined at that hour beat CNN by less than 100,000 households.

Among the networks, ABC, anchored by Peter Jennings, led the local ratings race for most of the afternoon and evening, with NBC and Tom Brokaw a close second. CBS and Dan Rather lagged far behind, often with less than half the audience of the other two networks and CNN.

In the network prime-time ratings for the nation’s 25 largest markets, ABC’s war coverage earned a 26% share of the available audience. NBC finished with a 22 share and CBS checked in with a 16. National ratings for CNN were not available at press time.

Spanish-language stations also drew big audiences for news of the war. At 6:30 p.m., for example, more than 350,000 homes were tuned to news on KMEX Channel 34 and KVEA Channel 52, about double the audience those two stations usually attract at that hour.

As for the four VHF independent stations, all of which periodically supplemented the CNN feed with their own anchors and their own reporting, KTLA finished first with a 9% share of the audience for its continuous coverage of the war, from about 3:45 p.m. Wednesday until 2 a.m. Thursday morning. KCAL, which used its own on-air news staff more than the other three stations, came in second with 7% share of the audience, while KCOP Channel 13 and KTTV Channel 11 each earned a 5% share for that 10-hour period.