Floods shouldn’t be a surprise

By Bo Emerson

The Atlanta Journal-Constitution

Atlantans fear deadly tornadoes and hurricanes, but not too many worry about deadly rain. But deadly rain took nine lives last week, as swollen rivers and creeks washed away cars and houses.

Assistant state climatologist Pam Knox pointed out, “If you’ve got rivers, you’ve got floods.”

Atlanta’s deadly rain was worsened by a few unlikely, interlocking events — a bizarre weather pattern, arriving on ground already saturated by preceding days of steady precipitation.

“This was like pulling the one-armed bandit in Vegas and having it come up three oranges,” said Tom Moore of The Weather Channel, based in Atlanta.

Some stream flows reached 500-year levels. Weather historians looked back to 1919 to find higher water.

“It’s sad, awful, quite scary when you look at how high the creek came,” said Eli Green, surveying the flood-damaged houses along Woodward Way off of Northside Drive in Buckhead. Dumpsters filled with reeking carpet, furniture and flooring lined up in front of houses that had been soaked by a record-high flooding of nearby Peachtree Creek

The unpredictability of the flooding caught many Atlantans offguard. Communities in Douglas County, where six people lost their lives, were hit hard, while others nearby were less affected. Green’s house, slightly up the hill from the damage along Peachtree Creek was also spared.

Terrain had much to do with it, but also the uneven nature of rainfall. “Hartsfield airport only had seven- plus inches this month; I live in Cumming and I had 20,” said Moore. “It’s not distributed evenly.”

Atlanta is on a ridge, at an elevation of 1,000 feet, and a long way from the ocean. These conditions perhaps encourage citizens to forego flood insurance. A story in Sunday’s Atlanta Journal-Constitution points out that only a small percentage are covered by federal flood insurance.

This despite the fact that the state encourages residents to insure against flooding. David Stooksbury, state climatologist, and an engineering professor at the University of Georgia, said “it’s a fallacy for anybody who thought they were safe. . . We particularly encourage people in Middle and North Georgia [to buy flood insurance] because we know flooding associated with tropical disturbances does occur.”

That’s what happened with Hurricane Ivan in 2004 and Tropical Storm Alberto in 1994.

What made last week’s downpour unusual was that it was not a tropical disturbance, but a “stalled” low pressure area. Cut off from the jet stream, and hovering over the Mississippi River, it acted liked a pump sucking moisture from the Gulf of Mexico into Georgia skies.

As odd as this weather is, Moore pointed out that on Friday a similar pattern was stalled over North Africa, causing flooding deaths in Tunisia.

Stooksbury said many deaths in Atlanta could have been prevented if the victims had backed away from standing water. The National Weather Service promotes a campaign called “Turn Around, Don’t Drown,” encouraging drivers to stop, back up, and leave a road covered with water. “If you literally cannot see the road, you don’t know what’s there,” he said. “It’s very difficult to judge the depth of water over a roadway.”