Temperatures made a barely noticeable dip on the 11th day of 100-degree heat Wednesday, but the stress on California's electric grid eased slightly, as did the possibility of rolling blackouts.

A dairy cow drinks water from a trough at the Zylstra Dairy Farm in Turlock, California. More than 70 people may have died in California's record-breaking heat wave, a state official said as temperatures appeared to ebb.[AFP]

The number of deaths believed to be caused by the heat rose sharply, reaching 83 since the heat wave started baking the state July 16. The heat and the increased power use blew out thousands of transformers, and farmers reported animals dying in the fields, and fruit and nuts scorched on the vine.

Hundreds of thousands of homes and businesses lost power at the peak, but just a few thousand remained in the dark Wednesday. Still, the widespread failures have left little opportunity for routine maintenance.

The coroner's office in Fresno County, which has reported 20 deaths as likely heat-caused, had bodies stacked two to a gurney because there were so many. Coroner Loralee Cervantes said that her staff was doing autopsies nonstop and that decomposition of some bodies made the cause of death difficult to determine.

Nineteen deaths were reported in neighboring Stanislaus County, and seven in Sacramento County. In all, 18 counties reported heat-related deaths.

Near Mexico, the Border Patrol found the body of one illegal immigrant whose death might be heat-related. It was unclear whether that death was included in the heat wave death toll.

Border Patrol agents also discovered one seriously dehydrated immigrant who was returned to Mexico and three women were hospitalized after being abandoned in the locked trunk of a car for 90 minutes by a driver who ran away after spotting a Border Patrol checkpoint.

Other states also attributed deaths to heat. Oklahoma said two people whose homes lacked air conditioners were the latest victims there, bringing to 10 the number of heat-related deaths since July 13.

An achingly slow cooling trend will cause highs to drop a few degrees by the weekend in California, according to National Weather Service forecaster Jim Dudley.

"We're seeing some relief coming, if you can call 105 relief," he said. "We're inching away from this super hot air mass we've had over us, though it's tricky. ... It's hard to get those things to move."

The record power usage on Monday and Tuesday had prompted power grid managers to declare an emergency and warn of possible involuntary rolling blackouts. Now the managers are waiting for cooler weather to begin assessing the damage and do maintenance, said Gregg Fishman, a spokesman for the grid manager, Independent System Operator.

"We have some balancing to do to allow as much maintenance as we can while we're in a cooling spell," he said. The company is now focusing on restoring power to those still without it.

More than 1,100 Pacific Gas and Electric Co. transformers were damaged by the heat, leading to about 6,000 outages affecting over 1.2 million customers since Friday, company spokesman Brian Swanson said.

The St. Louis area and the New York City borough of Queens slowly were returning to normal more than a week after weather-related power blackouts.

About 51,000 customers around St. Louis still were without electricity, according to Ameren Corp. Two storms July 19 and July 21 had knocked out power to more than a half-million customers.

A sixth death was blamed on the storms and blackout; the man died Wednesday in a fire that started while he was working on a power generator in East St. Louis, Ill.

In Queens, the last of the 100,000 people affected by a 10-day outage had their power restored, but the Consolidated Edison utility still warned of lower voltage and occasional outages.

California's inland valleys have registered some of the highest temperatures during the heat wave, with highs of around 115 and lows of about 90 degrees.

Farmers who face sun-baked crops and lower milk production are rushing farmworkers to the fields well before dawn so they can get out by late morning, when temperatures creep above 100.

Even with misters and fans to keep cattle cool, experts estimate as much as 2 percent of the state's dairy herd may die.

The surviving cattle are producing less milk, farmers said. Dairy production in the state - No. 1 in the nation was down as much as 15 percent in the past few days, according to the California Farm Bureau.

Though this is peak harvest time for fruits like peaches and nectarines, the heat stops the ripening process. Tomatoes being grown for salsa, ketchup and pasta sauces were found split in the fields, which will make them hard to sell.

It's too early to say what percentage of crops may be lost.

The heat might mean a slightly smaller harvest of wine grapes, said Karen Ross, president of the California Association of Winegrape Growers. When temperatures rise, vines stop growing to conserve water.

"They're just like people," she said. "They kind of shut down when it gets this hot."