If the warmer weather tempts you to jump in the lake in the days ahead -- don't.
"Even though Lake Lanier may be full or near full and the days are calling you to come out and play, enjoy the spring weather from the shoreline until those bodies of water warm up substantially," said Forsyth County Fire Capt. Jason Shivers.
Shivers added that most local swimming pools are also not warm enough for swimming. Even for experienced swimmers, the water can be dangerous.
"Cold water will shock your body, cramp your muscles and most likely cause you to drown," he said.
Brian Lynn, a meteorologist with the National Weather Service, noted that it takes water much longer than air to heat up. In fact, it's typically the end of May before the lake is warm enough for people to swim.
"When the air temperature starts warming up, the lake water responds," Lynn said. "It takes a tremendous amount of heat to change the temperature of a volume of water.
"Lake Lanier is a sizable lake -- is the biggest lake in the boundaries of Georgia -- and it also has a significant depth. That all contributes to the amount of heat it takes to warm it up."
While it is spring break this week, and lake visitation may rise with the temperatures this weekend, residents are urged to take precautions.
Shivers stressed the use of personal floatation devices when spending time on a boat or whenever entering the water.
According to the Centers for Disease Control and Prevention, drowning is the second-leading cause of unintentional, injury-related death for children ages 1 to 14.
Natural bodies of water like Lanier are deceptive because the depth of the water can change dramatically within a few steps of the shore.
According to the CDC, most drownings among those age 15 or older occur in natural water settings.
"You can't judge a book by its cover," said Hall County Fire Marshal Scott Cagle. "The flowers may be blooming and it's 70 degrees, but the water is still very cold and that can be very, very dangerous."
Boating and other water activities can be especially dangerous for nonswimmers.
Cagle said that when the lake is at full pool, as it is now, places where swimmers may have once been able to touch the ground may be too far under water.
The lake's first drowning of 2011 occurred in March when Roy Belrose, 66, of Buford was found in the lake by a neighbor.
Even for those who can swim, cold water is dangerous.
"When your body is 98.6 degrees at a normal temperature, you shock it with water that is 50 degrees," Cagle said. "Your body is not expecting that and you lose body heat faster in the water than you do on land."
Cagle said people who plan to be out on the lake fishing or boating need to follow all boating regulations and keep life jackets on board. He also recommended swimming and CPR classes.
"We just want people to prepared for the worst," Cagle said.
Melissa Weinman of the FCN regional staff contributed to this report.