Rainfall record: 2018 already the second-wettest year on record, unlikely to take top spot

Sam DeGrave | The Citizen-Times

ASHEVILLE — It didn't freeze as feared, but rainfall Thursday nudged the Asheville area closer to reaching a record year for precipitation.

But for this year to unseat 2013 as Asheville's wettest year, the city would have to record nearly double what has been average for the time spanning from mid-November though the end of the year.

Asheville typically gets 5.82 inches of precipitation in the last 45 days of the year. It would need more than 8.4 inches to break the current record of 75.22 inches.

"It's doable but probably not likely," said Justin Lane, a meteorologist based in the National Weather Service's Greenville-Spartanburg office.

And that's probably a good thing. This year — with 66.82 inches of precipitation — already ranks as the second wettest on record, having topped a mark set in 1973.

And the weather service is predicting above average precipitation this winter thanks to a weak El Niño in the Pacific.

Weather wonks might enjoy seeing this year take the top spot, but breaking the record would likely mean hazardous weather.

"It would mean you'd probably have at least one good winter weather event," Lane said Thursday. "But as wet as it's been lately, with that much precipitation through the end of the year, it would bring potential for flooding."

The wettest December on record, for example, was recorded in 2009, when Asheville saw 9.16 inches of precipitation, much of which fell as snow. Not surprisingly, that winter was Asheville's third snowiest in the last 149 years.

In winter, flood conditions are triggered by smaller amounts of precipitation. The grass has gone dormant and is unable to soak up as much moisture as it does in the summer and cold temperatures can make the soil less permeable, Lane said.

Asheville has already seen more than its share of flooding this year due, in large part, to three tropical systems.

The first dumped inches of rain on Asheville in May, which broke the record for wettest month. The Asheville Regional Airport recorded 14.68 inches of rain in May. August of 1940 previously held that title with 13.75 inches of precipitation.

When an unnamed tropical system moved through the region in late May, Buncombe County experienced widespread flooding. From Biltmore Village to Black Mountain, roads were submerged and residents were stranded.

The Black Mountain Fire Department evacuated more than 75 people during that rain event.

Lane said the weather service doesn't attribute this year's rainfall totals to any one pattern or weather trend. To understand why this year was so wet, he'd have to look back over the data on a "storm-by-storm-type basis," he said.

Two storms in particular played an out-sized role in 2018's run at the rainfall record.

Hurricanes Florence and Michael, which hit in September and October respectively, "weren't an insignificant contributor" to the years high precipitation total, Lane said. Neither September nor October, however, was record-setting.

Wettest Years on Record (Totals current as of Nov. 15, 2018)

2013 — 75.22" 2018 — 66.82" 1973 — 64.91" 2009 — 62.13" 1989 — 60.63" 2003 — 59.46" 1994 — 57.46" 1979 — 57.44" 1975 — 56.92"

1990 — 55.87"