DETROIT >> Hurricane Harvey took a toll on U.S. auto sales in August, but the storm could boost sales this fall as people replace flooded vehicles.

U.S. sales of new cars and trucks fell 2 percent in August, according to Autodata Corp. Harvey hurt demand in the Houston area — the ninth-largest vehicle market in the nation — cutting U.S. sales of new cars and trucks by an estimated 20,000 vehicles, forecasting firm LMC Automotive said.

Not everyone reported bad news today. General Motors said its sales rose 7.5 percent compared with last August. Toyota’s were up 7 percent and Volkswagen’s rose 9 percent. All three automakers reported strong sales of SUVs.

But Hyundai’s sales plummeted 25 percent. Nissan’s sales dropped 13 percent and Fiat Chrysler’s sales were down 11 percent. Ford and Honda both saw sales drop 2 percent.

U.S. auto sales were initially expected to increase slightly in August compared with a year ago, breaking a seven-month streak of sales declines. U.S. sales are plateauing after reaching a historic high last year, but August had one more business day than last year, and buyers were getting good deals on popular outgoing models like the Toyota Camry as new models hit dealerships.

Sales will likely pick up soon because people with damaged cars will need to replace them quickly. In the month following Superstorm Sandy in 2012, vehicle sales in the New York area jumped 49 percent, said Jonathan Smoke, the chief economist for Cox Automotive, the parent company of Kelley Blue Book.

Smoke estimates that 300,000 to 500,000 vehicles will need to be replaced as a result of Harvey. That demand will help automakers, who can move their excess inventory to Houston. But lower inventory in the rest of the country will mean consumers will be less likely to find good deals, Smoke said.

Until last Saturday, August was shaping up to be a strong month at the eight Bayway Auto Group dealerships that Darryl Wischnewsky owns in the Houston metro area. Then came Harvey. None of Wischnewsky’s dealerships suffered flooding or other damage in the storm, but he says he’s seen other dealers up and down the freeways lose all of their inventory and their buildings have been damaged.

His group, which includes Lincoln, Chevrolet, Fiat Chrysler, Volkswagen and Volvo dealers, shut down Aug. 26 as the storm approached and just started reopening on Aug. 31. Losing the Saturday alone probably cost 60 to 70 sales, Wischnewski said.

“Just that one day in Houston, that’s thousands of cars,” he said.

For August, automakers said:

>> General Motors Co. said its sales jumped 7.5 percent to 275,552. GM said sales of small SUVs like the Chevrolet Equinox jumped 47 percent for the month.

GM also said its sales to rental car fleets rose 29 percent to 7,600 vehicles. But August was an anomaly; GM said it’s still on track to cut low-profit rental car sales by 50,000 vehicles this year.

>> Toyota Motor Co. said its sales rose 7 percent to 227,625. Toyota’s car sales dropped 7 percent, but its SUV and truck sales jumped 19 percent thanks in part to strong sales of the RAV4 small SUV.

>> Ford Motor Co. said its sales fell 2 percent to 209,897. Ford sold more than 77,000 F-Series pickups in August, a 15 percent gain over last August. But its SUV and car sales were down.

>> Fiat Chrysler’s sales fell 11 percent to 176,033. Sales of some individual models, like the Jeep Grand Cherokee SUV and Dodge Caravan minivam, saw strong growth, but sales of the company’s best-seller, the Ram pickup, dropped 7 percent.

>> Honda Motor Co.’s sales fell 2 percent to 146,015. In a reverse of most other automakers, Honda saw increased car sales while sales of its trucks and SUVs fell.

>> Nissan Motor Co.’s sales fell 13 percent to 108,326. Luxury Infiniti sales grew as that brand introduced new models, including the QX30 SUV. But Nissan brand sales fell 15 percent.

>> Hyundai Motor Co.’s sales dropped 25 percent to 54,310. Hyundai said its Tucson SUV sales rose 28 percent, but it cut sales to rental companies and other fleets by 53 percent.