MERCED -- As the temperature continues to rise -- hitting 104 Thursday -- so does the desire of many to cool off by jumping into their favorite swimming hole.
But that can be more dangerous than the extreme heat Merced and other San Joaquin Valley residents are dealing with this week, authorities warn. It just depends on where they decide to go swimming.
While the Merced River and Merced Irrigation District canals might look inviting, officials stress that both contain hidden dangers that can turn a cool dip into sudden tragedy.
Deputy Tom MacKenzie, Sheriff's Department spokesman, said the swift current and cold water make the river a place to be avoided. He said holes on the river bottom, submerged trees and other unseen hazards can be deadly.
A 6-year-old Bay Area girl drowned in the Merced River on Sunday while wading in an area with other family members nearby. Authorities said the part of the river she was in is shallow, but she apparently stepped into a deep hole and vanished without anyone noticing right away.
MacKenzie said even though the river isn't flowing as fast as it was a year ago, when there was a lot of runoff from a huge snowpack, it's still fast enough to get people into trouble, especially if they aren't good swimmers.
He said the river also is dangerous for rafters, particularly those who aren't experienced, don't have the property safety gear and are riding in cheap inflatables.
Don't be fooled, MacKenzie said, it isn't as calm as it looks on the surface. "We know it's hot," he added, "but we recommend people stay out of the river."
People should also stay out of the 800 miles of canals delivering irrigation water to farmers in the region, urged MacKenzie and Mike Jensen, spokesman for the Merced Irrigation District.
Jensen said canals aren't for swimming because pipes, gates and debris below the surface of the water can trap people. He added that the canal water is very cold and swift and can quickly overwhelm people.
Unlike the backyard swimming pool, Jensen said canals don't have stairs or ladders, so getting out is extremely difficult and compounds the danger.
Instead of the river or canal, MacKenzie suggested people try to find other ways to cool down.
That's good advice, with temperatures expected to hit 107 today in Merced and again Saturday. They aren't expected to drop below 100 until the middle of next week.
Staying cool could be even tougher in some parts of the state. The California Independent System Operator, which manages most of the state's power grid, said a Flex Alert would be in effect from today through Sunday evening. A Flex Alert calls on individuals, businesses and governments to voluntarily cut back on energy use from 11 a.m. to 6 p.m. to prevent operating reserves from falling to emergency levels. The first stage of California's three emergency levels is triggered when operating reserves are forecast to fall to between 7 percent and 6 percent.
Jensen said the MID is aware of the Flex Alert but doesn't anticipate problems.
"MID receives its power through the Turlock Irrigation District, which maintains many of its own generation assets," Jensen said. "We always encourage customers to conserve energy for their own financial benefit. We will be closely monitoring energy demand and usage over the next few days but expect MID customers to be generally insulated from problems." he said.
The Associated Press contributed to this report.