Dozens of people died this week in historic flooding that ravaged parts of the southern United States. The worst flooding hit the hollows of eastern Kentucky, a mountainous region unaccustomed to sustained tropical rains like the torrential rains seen this week. Here’s an inside look at how the atmosphere caused these catastrophic deluges.
MUST READ: Everyone needs an emergency kit at home. Here’s how to store yours
Toronto’s drought is linked to Kentucky’s catastrophic flooding
The same pattern that brought relentless rain to parts of the United States this week is also partially responsible for the unusual mid-summer dry spell we’ve seen in parts of central Canada.
The dry grass and withered bushes are an ever-present reminder of the relative lack of rain we’ve seen in places like southern Ontario in recent weeks.
Toronto would typically see about 75mm of rain in an average July. So far this month, the city’s international airport has seen only about 44mm of rain, just 58 percent of the average.
Where did all the rain go? Look at the pattern south of the border for an important 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 very wet for the past month. This ridge also acts as an atmospheric dam, gathering tropical moisture flowing northward 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 provide our much needed rain.
Unfortunately, this accumulated moisture has fueled persistent thunderstorms in places like St. Louis, Missouri and eastern Kentucky, two areas that experienced major flooding last week.
WATCH: Similar floods in Europe in 2021 likely enhanced by climate change
Kentucky is experiencing some of its worst flooding in recent memory
A stalled boundary over Kentucky late Wednesday, July 27 allowed persistent thunderstorms to develop and thrive in the moist air accumulated in the region. The storms had a large supply of atmospheric moisture to draw upon, and these juicy storms kept moving through the same communities for hours at a time.
Mind-blowing rainfall accumulates at the end of the torrent. Some communities in the region saw more than 250mm of rain on Thursday morning. The rains had an immediate and devastating impact on communities caught in the storms.
Water levels along the North Fork Kentucky River in the town of Whitesburg rose at an impressive rate as rain fell on the hills that make up the eastern third of Kentucky.
The previous all-time record crest for the river at Whitesburg occurred on January 29, 1957, reaching 14.70 ft (4.48 m). The flood of 1957 was a generational tragedy for the region.
This week’s flooding raised the river to at least 20.91 feet (6.37 m) before the gauge stopped reporting.
Floodwaters rushed into neighborhoods before many residents had a chance to react. The rip currents washed away vehicles and houses alike, causing significant loss, injury and death.
“We are currently experiencing one of the worst and most devastating flood events in Kentucky history,” Gov. Andy Beshear said in a state of emergency declaration the morning of the flood.
At least 25 people were confirmed dead in the flooding Saturday afternoon, according to a statement issued by Gov. Beshear’s office, and the total is expected to rise as those who are not among the debris
St. Louis breaks all-time daily rainfall record
Two days before flooding rains inundated eastern Kentucky, a major city on the Mississippi River saw its own historic deluge.
Tuesday, St. Louis, Missouri, recorded the most rainfall ever seen in a single 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 record by leaps and bounds, the Weather Service office reported National (NWS) of the city in a summary of the event. .
(Infographic courtesy of NWS St. Louis/NOAA.)
An all-too-familiar situation occurred in the metropolitan area of St. Louis following torrential downpours. Widespread flooding closed major roads and flooded neighborhoods, forcing emergency officials to conduct water rescues across the region.
According to the NWS summary, one person died in the flooding in St. Louis after the water overtopped his vehicle.