Republican U.S. Senate candidate Joni Ernst (R) of Iowa has released a new TV ad saying she’ll know how to cut pork in Washington. (YouTube: Joni Ernst)

In one of the most competitive Senate races in the country, political ads in Iowa are running nonstop on Des Moines station WHO-DT. And it can hardly keep up with the demand.

At a time when fewer people are watching news on TV, the station added an hour-long daily news program focused on politics — and hired four journalists to fill the time — just so it can sell more lucrative commercials featuring scenes such as Republican candidate Joni Ernst surrounded by snorting hogs.

Dollars are also flooding into modest local stations in Alaska, Arkansas and Kansas — many unaccustomed to such demand because they are not in traditional presidential battleground states. Total political advertising in 2014 is expected to reach a record $2.4 billion, up $100 million from four years ago, according to estimates by the Kantar Media research firm.

This year’s deluge of political ads is being driven largely by super PACs and other independent groups seeking to shape the hard-fought battle over control of the U.S. Senate. While the volume of spots for House and governors’ races is down this fall compared with 2010, the number of Senate ads is up nearly 12 percent, according to a new analysis of Kantar data by the Wesleyan Media Project.

The ads are a boon for local stations, which are struggling to retain their audiences. Like newspapers, the local TV news business has been upended by the Internet, which has radically altered how people find out what is going on in their communities.

Election Lab: See our current forecast for every congressional race in 2014

But one thing remains largely unchanged: the belief that television ads are the best way to reach voters.

While campaigns are increasingly embracing online advertising, they still rely heavily on the tried-and-true technique of reaching voters on the airwaves. There, they can find a guaranteed audience of the most faithful voters: older people, who are particularly valuable in low-turnout midterm elections.

That demographic is a die-hard group of TV fans, watching more hours per day than ever. Live television viewing was down 13 percent for all age groups with the exception of viewers 55 and older, who are steadily watching their shows at their scheduled broadcast times, according to Nielsen. The median age of a broadcast or cable television viewer during the 2013-2014 TV season was 44.4 years old.

These viewers are also most likely to make it to the polls.

“Advertisers want to go where the eyeballs and ears are. There is a tendency for people who watch local news to be more likely to vote,” said Dennis Wharton, executive vice president of communications at the National Association of Broadcasters.

Gannett this month attributed a 15 percent rise in quarterly revenue to political advertising at its television stations and said it expected a spike in ad spending in the last weeks ahead of the November elections. CBS President Leslie Moonves famously said in 2012 that “super PACs may be bad for America, but they are very good for CBS.”

Local ad-buying frenzy

The air war is playing out in states with competitive races such as Iowa, where spending by candidates and their outside allies has already topped $82 million, according to campaign finance data compiled by the Sunlight Foundation.

This year’s midterm races have seen a record amount of outside spending.

The candidates are also fueling the last-minute ad blitz. Democratic contender Bruce Braley’s campaign is spending $63,825 to advertise in the week before Election Day on WHO. That has bought him 60 of his 30-second commercials starting with “Today in Iowa” at 6 a.m. and going through the last news program at 10 p.m.

It cost Braley’s campaign $2,290 for one 30-second advertisement against Ernst during the highly rated program “Wheel of Fortune” between 6:30 and 7 p.m. on Nov. 3, according to political advertising filings at the Federal Communications Commission. In August, it cost $495 to advertise during the game show.

“This reinforces the strong position that TV has in political messaging,” said Dale Woods, the general manager of WHO.

The station’s new 4 p.m. news program offers interviews with candidates and was created in response to greater interest in the races by viewers, he said, noting that “political campaigns always prefer news because there is a higher propensity to get out to voters.”

Woods said that by replacing “Ellen” with the political newscast, the station gets to keep all of the revenue from ads, rather than share it with Warner Bros., its syndication partner for the daytime talk show.

In Arkansas, where Sen. Mark Pryor (D) is in a tight race with Tom Cotton (R), the Fort Smith station KFSM-TV has seen a 34 percent jump in advertising this year compared with last year.

“It’s a great situation, and I’m not complaining, but when you have that kind of tidal wave of advertising interest over the top, it puts pressure on the station when we have limited inventory,” KFSM General Manager Van Comer said.

The flood of ads surged dramatically in October as conservative groups ramped up their spending, sending prices climbing sky-high in cities such as Little Rock, Denver and Manchester, N.H. There, WMUR-TV was charging $1,400 per gross rating point this month — six times the rate before Labor Day.

“Every day in the month of October must be like Christmas morning for TV stations in these hyper-competitive media markets,” said Jesse Ferguson, who runs the Democratic Congressional Campaign Committee’s independent expenditure program, which has invested more than $60 million on behalf of Democratic candidates.

The top market for TV ads this cycle has been Denver, which has been bombarded by 78,386 spots, according to the Wesleyan Media Project. In second place is Little Rock, which has fielded 51,758 spots.

Jennifer Hungerbuhler, who oversees local spending for Amplifi­, a division of the global media services company Dentsu Aegis Network, said nonpolitical advertisers are getting crowded off the air by independent groups willing to pay top dollar to influence campaigns. At WHO, 70 percent of ads are political, and almost all local ads at KTUU-TV in Anchorage are related to campaigns and ballot measures such as the legalization of marijuana.

An overreliance on TV?

Even small markets such as Charleston-Huntington in West Virginia have been affected, targeted by ad buyers for not only a competitive House race in the state, but also because its stations reach voters in Ohio and Kentucky.

“Political advertising is a huge growth area for TV,” said Elizabeth Wilner, senior vice president for political advertising at Kantar. “For places with close Senate rates like Arkansas, Alaska and Louisiana, this is about as close as you can get to a presidential race and the gold rush in advertising that comes from that.”

But some political strategists believe campaigns are still too reliant on splashy buys on broadcast television, which offer little precision in targeting voters.

Since Labor Day, $80 million out of $111 million spent on broadcast television on congressional campaign ads has been wasted on viewers outside the intended district, according to an analysis by the GOP technology and media-buying firm Targeted Victory.

“People buy broadcast because it has huge reach, but a lot of those people can’t vote for you,” said co-founder Zac Moffatt.

Nevertheless, this year the TV campaigns started earlier than ever.

The race to persuade voters in Alaska began in the late fall of 2013, said Andy MacLeod, general manager of KTUU.

So far, the campaign between Democratic incumbent Mark Begich and GOP challenger Dan Sullivan has drawn nearly $38 million in independent spending by super PACs, advocacy groups and party committees, according to the Center for Responsive Politics.

That’s meant a bonanza for KTUU, which has run the greatest number of political ads this cycle of any station in the country, according to Kantar. The station is particularly attractive because of its reach in the Anchorage area.

The station launched a Sunday morning politics show during the summer and has hosted more political debates.

“It’s always been a good market, but this year all the political forces came together on all points of the compass with federal, gubernatorial, major ballot issues on an oil tax, mining and marijuana,” MacLeod said.

Still, the station is regarding the ad boom with prudence. The unexpected windfall will probably go to paying debt and continuing expenses.

“You can’t really count on political money,” he said.

8To watch a video about political spending, go to wapo.st/MidtermSpending. For a graphic on the midterm elections forecast, go to wapo.st/electionlab.