Dozens of people have died this week in historic flooding that has swept parts of the southern United States. The worst flooding hit the lowlands of eastern Kentucky, a mountainous region unaccustomed to sustained tropical rains like the torrential downpours we’ve seen this week. Here’s an inside look at how the atmosphere caused these catastrophic floods.
MUST READ: Everyone Needs a Home Emergency Kit. Here’s how to stock up on yours
Toronto’s dry spell is tied to Kentucky’s catastrophic flooding
The same pattern that brought relentless rainfall to parts of the United States this week is also partially responsible for the unusual summer dry spell we’ve seen in parts of central Canada.
Dry grass and withered brush are a constant reminder of the relative lack of precipitation we’ve seen in places like southern Ontario in recent weeks.
Toronto typically gets about 75mm of rain in July. So far this month, the city’s international airport has seen only about 44 mm of rain – just 58 percent of the average.
Where did all the rain go? Look at the pattern south of the border for a major piece of the puzzle.
A large ridge of high pressure over the southeastern United States has kept this part of the world very warm and terribly humid for the past month. This ridge also acts as an atmospheric levee, collecting tropical moisture that flows north from the Gulf of Mexico and trapping it over the southeastern states.
As a result, we haven’t had many opportunities for deep moisture to flow over southern Ontario and deliver much needed rain.
Unfortunately, this trapped moisture is fueling persistent thunderstorms over places like St. Louis, Missouri, and eastern Kentucky, two areas that experienced massive flooding this past week.
WATCH: Similar floods in Europe in 2021 likely boosted by climate change
Kentucky is suffering some of its worst flooding in recent memory
The boundary stalled over Kentucky on the evening of Wednesday, July 27, allowing persistent thunderstorms to develop and thrive in the moist air accumulated over the region. Thunderstorms had a huge reserve of atmospheric moisture to draw on, and these juicy storms continued to move over the same communities for hours at a time.
Staggering amounts of rainfall accumulated by the end of the downpour. Some communities in the region saw more than 250mm of rain by Thursday morning. The rainfall had an immediate and devastating impact on the communities left behind by the thunderstorms.
Water levels along the North Fork Kentucky River in the town of Whitesburg rose at a breathtaking rate as rains poured into the hills that make up the eastern third of Kentucky.
The previous all-time river record at Whitesburg occurred on January 29, 1957, peaking at 4.48 m (14.70 ft). The flood of 1957 was a generational tragedy for the region.
This week’s flooding raised the river to at least 6.37 m (20.91 ft) before the gauge stopped reading.
Floodwaters swept through neighborhoods before many residents had a chance to react. Storm currents swept away vehicles and homes, resulting in significant losses, injuries and deaths.
“We are currently experiencing one of the worst and most devastating floods in Kentucky history,” Gov. Andy Beshear said in an emergency declaration the morning of the flooding.
At least 25 people were confirmed dead in the floods as of Saturday afternoon, according to a statement issued by Gov. Beshir’s office, and the total is expected to rise as those missing are found amid the debris.
St. Louis breaks all-time record for daily rainfall
Two days before floodwaters inundated eastern Kentucky, a major city on the Mississippi River suffered its own historic deluge.
On Tuesday, St. Louis, Missouri, recorded the most rain it had ever seen in one day. The city’s international airport saw 219.4 mm (8.64 inches) of rain between July 25 and 26, breaking the previous 106-year-old record by leaps and bounds, the city’s National Weather Service (NWS) office said in a summary of the event. .
(Infographic courtesy of NWS St. Louis/NOAA.)
An all-too-familiar situation played out in the St. Louis metro area after heavy rains. Widespread flooding closed major thoroughfares and inundated neighborhoods, forcing emergency services to carry out water rescue operations across the region.
One person died in the flooding in St. Louis after water flooded his vehicle, according to the NWS summary.
Add Comment