LAWRENCEVILLE - The National Weather Service deemed Monday's flooding historic.
Climatologists expect to see 8 inches of rainfall in a 24-hour period only once in 100 years in north Georgia, leaving the excessive rain that fell over the metro area Sunday and Monday to go down in weather record books.
According to David Stooksbury, state climatologist, many locations in the northern part of the state had exceeded 8 inches of rain in a 24-hour period by Monday afternoon.
The National Weather Service indicated 12 to 15 inches of rain had fallen beginning Sunday and continuing through Monday. Scattered areas of heavy rain were expected to add 1 to 2 inches as no significant break in rainfall was expected Monday night.
The threat for continued or worsening flooding remained high.
"This is similar to what occurred across central Georgia and into south Georgia during (Tropical Storm) Alberto," said meteorologist Matthew Sena with the National Weather Service out of Peachtree City. "These types of rainfall totals over this period of time are probably not that dissimilar to what they saw in the Albany area during Alberto."
Stooksbury echoed that comparison, calling Monday's rainfall reminiscent of the 1994 storm that made landfall in Florida and then stalled over parts of south Georgia and Alabama for two days, causing massive flooding.
At 4 p.m. Monday, Suwanee Creek was 4.4 feet above its flood stage of 8 feet. The National Weather Service indicated waters would continue to rise near 13.4 feet Monday night, an all-time record high, and fall below flood stage Wednesday morning. At 14.5 feet, major flooding would begin and water would start to enter Swift Atlanta Company on Swiftwater Park Drive.
The Gwinnett Department of Water Resources indicated Monday afternoon the Yellow River had crested, eclipsing the flood stage it is expected to exceed only once in 100 years. The swelling river forced the nearby sewage treatment plant to close.
Lake Lanier's water level stood at 1,066.61 feet above sea level at 4 p.m. Monday, a little less than 41/2 feet shy of full pool. The lake was up more than two feet since its Friday measurement.
According to the National Weather Service, Gwinnett residents should begin to see rains let up Wednesday.
"The upper level system that's been sending weak disturbances that's been helping to generate this has shifted," Sena said. "Our chances (of rain) should begin to decrease late (today) and into the middle, second half of this coming week."
Sena said even as the rain lets up moving into Wednesday, hazards will still exist.
"It's going to take a while for this water to come down," he said. "Any heavy rain could cause at least some localized flooding problems later in the week, but we're not expecting the widespread problems we're having now."
Rainfall totals for the past week at DeKalb Peachtree Airport, the National
Weather Service's closest automated station to Gwinnett County