North Georgia flash flooding: what a catastrophic warning means, and a calm checklist for home

What happened overnight

NWS Peachtree City issued its first flash flood warning for Fannin, Gilmer, Murray and Union counties at 8:55 PM on Wednesday, November 4, saying 1 to 2 inches of rain had fallen. At 9:30 PM it issued a second warning, with its considerable tag, for northwestern Fannin and north-central Gilmer, where 3 to 4 inches had fallen. At 10:47 PM, after local law enforcement reported heavy rain "resulting in mudslides and water rescue," it extended that warning and declared a "FLASH FLOOD EMERGENCY for Southern Fannin and Northern Gilmer," with 5 to 6 inches already down. It named Blue Ridge, Higdon and Colwell.

NWS storm reports log what people saw that night. Fannin County's emergency manager reported a "Water rescue with water in residence" south of Epworth at 11:47 PM. Reports from Gilmer and Murray counties describe water in homes, and roads north of Cherry Log in Fannin County were reported impassable due to a mudslide. A mesonet site 2 miles northwest of Blue Ridge recorded "11.19 inches in under 6 hours."

McCaysville, the morning after

At 5:08 AM on November 5, NWS said no additional rainfall was expected but flooding impacts would continue, and declared a "FLASH FLOOD EMERGENCY for McCaysville," in north-central Fannin County. A storm report at 6 AM, from a member of the public, described 2 to 3 feet of water near Tennessee Avenue and Blue Ridge Drive, and said the Toccoa River gauge "crested at a new record of 18.05 feet."

At 8:57 AM, NWS said "emergency management reported significant flooding in and around McCaysville." By 10:53 AM it wrote: "Flood waters are starting to slowly recede. Please continue to heed remaining road closures." It cancelled the last flood warning, for Fannin County, at 2 PM.

NWS's alerts and storm reports confirm water rescues but give no total, and we have not found a count from Georgia's emergency management agency or the counties. We will add one when an official source publishes it.

What a catastrophic flash flood warning means

NWS says "A Flash Flood Warning is issued when a flash flood is imminent or occurring." Many flash flood warnings carry a damage-threat tag. A considerable tag means "An unusually dangerous weather hazard that poses a considerable threat to life and property is likely ongoing."

Catastrophic is the top tag. NWS describes it as "An extremely dangerous weather hazard capable of catastrophic damage and a severe threat to human life is likely ongoing," and says such a warning includes the phrase "FLASH FLOOD or TORNADO EMERGENCY." NWS's wording is "likely ongoing": the flooding is probably already happening.

The instruction in this week's emergencies was plain: "Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order." If a catastrophic warning ever covers your area, move to higher ground and don't travel unless you are fleeing flooding or under an evacuation order. Our guide to emergency alerts on your phone shows how to make sure warnings like these reach your phone.

Is more rain coming?

Not this week, NWS says. Its Peachtree City forecast discussion on the afternoon of November 5 says "New significant rainfall totals are not expected as dry air is rapidly filtering in," and "Calm and pleasant fall weather is expected" through the long-term forecast. It still asks people to "avoid driving on closed roads."

As of 6 PM ET on November 5, NWS showed no active watches, warnings or advisories in Georgia. Your state page and our live alerts page show anything new.

If water reached your home

Go back only when it is safe. NWS says: "Do not enter a flood damaged home or building until you're given the All Clear by authorities." Stay out of the water itself. CDC says "Stay out of floodwater," because it can carry sewage, chemicals and debris. If you must step in, CDC says wear "rubber boots, rubber gloves, and goggles."

• Electrical system first. CDC says "Have an electrician check the house's electrical system before turning the power on again," and never turn power on or off, or use an electric tool, while standing in water.
• Generators outside only. If you run one during cleanup, CDC says never closer than 20 feet to any door, window or vent, even with them open. Our generator safety guide explains why.
• Assume mold. CDC says "If your home has been flooded and has been closed up for several days, assume your home has mold." Dry it out with fans blowing outward.
• Photos before cleanup. FloodSmart says "Take clear pictures and videos of damaged items before cleaning, fixing or throwing them out."

If you're on a private well

If your home is on a private well, flood water can reach it. CDC says: "If extensive flooding has occurred or you suspect that the well may be contaminated, do not drink the water." Until it has been tested, boil it, "rolling boil for 1 minute," or use bottled water.

CDC says to contact your local or state health department or agriculture extension agent for advice on disinfecting your well. Before the well pump goes back on, CDC says a qualified electrician, well contractor or pump contractor should check its wiring. CDC recommends having a contractor disinfect the well, then waiting at least 7 to 10 days before having the water tested. Water contaminated with fuel or toxic chemicals can't be made safe by boiling or disinfection; CDC says use bottled water until you know it's safe. Our boil water guide covers boiling and storing water.

What you don't need to do

You don't need to buy anything because of this flood. Don't drive out to look at the damage: NWS says "Do not visit disaster areas," because sightseers can get in the way of rescue crews. On any flooded road, turn around. NWS says just 12 inches of rushing water can carry away most cars, and "The road may have collapsed under that water." Our guide to driving through flood water explains why.

FloodSmart says "Most homeowners and renters insurance does not cover flood damage," and a new flood policy usually starts 30 days after purchase. It won't help with this flood, but it is worth a look before the next one. Our flood preparedness guide explains how it works.