The Most Staggering Facts About Historic St. Louis Flooding

Torrential rain hammered St. Louis late Monday night into Tuesday morning, smashing an all-time rain record and triggering widespread flash flooding throughout the metro area.

Follow our live updates page for the latest breaking news on this major flash flood.

There are aspects of this event that stunned even our team of meteorologists. Here are just a few of those factoids.

St. Louis' Wettest Day Of Record

St. Louis Lambert International Airport had already shattered the city's all-time rain record for any single day before some of you woke up. Several reporting stations measured over 10 inches of rain.

It Only Took About 6 Hours

That previous record was a record for a full day.

Tuesday morning, that record was topped in only about six hours.

According to NOAA Weather Prediction Center warning coordination meteorologist Alex Lamers, the rainfall rate measured early Tuesday morning had only a 0.1 percent chance of happening in any year in St. Louis, based on historical data.

More Than Twice A Month's Worth

St. Louis averages 3.93 inches of rain for the entire month of July.

They picked up more than double that amount in about six hours Tuesday.

Put another way, it was more than their average for July and August combined (7.31 inches).

One Fourth Of An Average Year's Worth

According to the National Weather Service, this 12-hour deluge provided roughly 25 percent of the metro's average precipitation for the entire year, which is about 41.70 inches.

The Old Record Was From A Hurricane Remnant

The wettest day on record in St. Louis prior to Tuesday was over 100 years ago.

That was from the remnant of what was once the 1915 Galveston hurricane, which dumped 6.85 inches in St. Louis on Aug. 20, 1915.

From Creek To Raging Torrent

One of the dangers of flash floods is how quickly a normally placid creek or stream can swell into a dangerous, life-threatening torrent.

A river gauge along Dardenne Creek in the western suburb of St. Peters rose over 21 feet in just over seven hours Tuesday morning.

That may not sound like much along, say, the Mississippi or Missouri Rivers. But this creek is usually only 1 to 2 feet deep.

A Classic Train of Storms on Satellite Imagery

The setup for this historic rain event was right out of summer's flash flood textbook.

Thunderstorms continually formed to the north of a stationary front and tracked from west to east over the same areas, like boxcars of a train over the same section of rail track.

Meteorologists refer to this as "training".

Vehicles Almost Completely Submerged

Flash flood events can often trap vehicles in floodwater.

It's the high-end events that can virtually completely submerge vehicles up to their roof, as was seen in parts of St. Louis Tuesday.

The flooding required not only numerous water rescues from vehicles, but also evacuations from homes. Some reportedly were forced to swim out of their homes.

(MORE: How To Stay Safe From A Flash Flood)

Perhaps the most stunning flooding we saw, however, was one of the city's Metrolink stations flooded. According to @NextSTL contributor @TonyInStLouis, the last time this immediate area experienced flooding on par with Tuesday was in the 1920s.

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