Call it climate change or call it a climate cycle that will eventually sort itself out. However you describe it, excessive rainfall is becoming a more common occurrence in Scott County and the northern Cumberland Plateau region, leading to more frequent floods that cause damages to roads and basements throughout the region.
This past weekend’s flood was just the latest in a series of high-water events in Scott County. The historic Burnt Mill Bridge was swept away as Clear Fork reached its highest crest there since the great 1929 flood. But stating that the river — which merges with New River just a couple of miles downstream from Burnt Mill to form the Big South Fork — reached its highest stage in 92 years doesn’t tell the complete story … the story of how flood stages on the Big South Fork river system have become increasingly common in recent years.
There have been significant floods in years past. In addition to the 1929 flood, there were memorable floods in 1969 and 1973 that stand out. But now the floods are coming more frequent.
Eleven miles downstream from Burnt Mill, at Leatherwood Ford, the U.S. Geological Survey’s water data only goes back to 1984 — a much shorter history than the gauge at Burnt Mill. But the data is revealing.
When flooding rains caused the Big South Fork to crest at 39.45 feet on Feb. 6, 2020, it was the highest crest recorded on the river in 36 years of records-keeping by the USGS. But the record didn’t last long. On Sunday — less than 14 months later — a new record was set when the Big South Fork crested at 42.38 feet.
Four of the five highest crests at Leatherwood Ford since 1984 have occurred in the past 10 years. In addition to the two most recent floods, the river crested at 32.05 feet on Nov. 28, 2011, and at 32.03 feet on April 23, 2017.
The lone exception was the river’s third-highest crest of 33.74 feet, which occurred on Sept. 17, 2004.
That April 2017 flood was memorable. Significant damage was caused to roadways. A portion of S.R. 456 on the far side of Paint Rock partially broke off, and Low Gap Road was completely washed out. Those were just two of the roads that were closed. The flood also caused damage to a number of homes throughout Scott County. Many called it the worst flooding Scott County had seen since 1973. A once-in-a-generation type of flooding event was what this newspaper called it.
Yet, within the next four years, there would be two floods that exceeded it. The February 2020 flood was called by some a “once-in-100-years” event, only to be exceeded less than 14 months later.
Last weekend’s rainfall was unprecedented. The Tennessee Valley Authority recorded 8.0 inches of rain at Burnt Mill in a 24-hour period from Saturday morning to Sunday morning (5.4 inches of rain were recorded in Oneida during the same time span). But heavy rain events have become commonplace.
An Independent Herald article in January 2020 was headlined, “Wet: The new normal?” It was written after a whopping 70.8 inches of rain fell in Scott County during the 2019 calendar year, making it the second-wettest year on record in Oneida, after the 2018 calendar year had become the second-wettest year with 69.1 inches of rain. At the time of that article, the four wettest years on record in Oneida had occurred in the last six years.
Nothing has changed since that time. The 2020 calendar year didn’t crack the Top 5 wettest years in Oneida — as 2015, 2019, 2018 and 2014 did — but it was the eighth-wettest year on record in Scott County, with 63.3 inches of rain. Throw in 2017 with 61.4 inches of rain, and six of the 10 wettest calendar years on record in Oneida have occurred in the past seven years. The only exception in that seven-year period was the drought year of 2016, when only 46 inches of rain fell in Scott County.
Here’s another way of summarizing it: If you go back to the 1950s, when National Weather Service records-keeping began in Oneida, the average annual rainfall in Scott County is 56.3 inches. But if you use a rolling 30-year average of the 1990s, 2000s and 2010s (1990-2019), that average jumps to 61.7 inches of rain per year. If you use just the time frame of 2000-2020, the average jumps to 63.6 inches of rain per year. And if you use the single decade of the 2010s (2010-2019), the average jumps to 64.4 inches of rain per year.
To be sure, Oneida has experienced prolonged wet periods in the past. The 1960s and 1970s were one such period, featuring the aforementioned floods of 1969 and 1973, along with several other high-water events. But the rolling 30-year average of rainfall from 1960 through 1989 was just 54.8 inches of rain per year. Even if you remove the 80s, which were somewhat drier than the 60s and 70s, the average rainfall in Oneida from 1960 to 1979 was 55.2 inches per year.
As Oneida has become wetter, the late winter and early spring periods have featured heavily in the excess. In fact, prior to 2021, Scott County had seen three straight years of record-breaking rainfall in February. It started in February 2018, which featured 10.8 inches of rain and was at that point the wettest February on record (breaking 1956’s 10.4 inches of rain). Then came February 2019, with 12.9 inches of rain. And, in 2020, February saw 11.0 inches of rain fall in Oneida.
February 2021 finally saw a break in the trend, as the weather pattern locally was dominated by colder-than-normal and drier-than-normal record. The 4.8 inches of rain that fell in Oneida during the month of February was the smallest amount of rain for the month since 2017, and the second-smallest amount since 2009.
But then came March, with 10.6 inches of rain, making it the fifth-wettest March on record in Oneida (two of the three wettest months of March on record came in 1973 and 1975).
Will the trend continue in April? If the start of the month is any indication, the answer is probably not. It will take 8.3 inches of rain this month to beat out 2017, which featured the big April flood, and 9.6 inches of rain to beat out 2003 for the wettest April on record in Oneida. But as last weekend showed, it only takes one major storm system to make a huge difference. Suffice to say, though, that Scott County and the rest of the region are overdue some quiet, tranquil weather.