St. Louis sits in a precarious place, nestled between two big rivers and crisscrossed with tributaries. The French trappers who founded the city in 1763 chose a spot high on a limestone bluff, close enough to the Mississippi River to get their goods to market but far enough away to avoid floods. But the city has long outgrown that origin story, if not the romance of the riverine location. Today, flooding is part of life in St. Louis, with six major floods since 2008 and two record-setting floods in the last three years alone. What’s more, with no surrounding mountains to run interference, the city is wide open to cold weather sweeping in from the north and hot, humid weather rising up from the south, and is prone to tornadoes. And when all else fails, there still can be extreme wind or monster hail. For all these reasons, St. Louis County and City landed on our top ten list for disaster-prone areas.
One of the worst floods in St. Louis history occurred during the holiday season in December 2015. Heavy rains poured seven to ten inches across St. Louis County on December 26th and 27th, causing multiple creeks and rivers to overflow. The rain fell so quickly that Deer Creek rose 11 feet in three hours, and the Meramec River crested at record levels. As a result, flooding was widespread and damaged nearly 900 buildings, including two wastewater treatment plants, the latter alone estimated to cost $16 million. The rains eventually subsided on December 28th, but the Meramec, Missouri, and Mississippi rivers all remained at high flood levels into January. Eighteen months later, the flood records set in 2015 were broken by another flood in April and May 2017. The floods hit many of the same areas, especially towns along the Meramec River, and shut down two major highways for multiple days.
Floods were not exactly unknown in St. Louis before 2015, and in fact the area had a similar incident as recently as 2008, when remnants of Hurricane Ike dumped rain over the region. There have also been near misses, such as the snowmelt in the summer of 2011 from record snowfall in the Rocky Mountains. States all along the Missouri River faced severe flooding as major dams had to release an unprecedented amount of water downriver. Fortunately, by the time the flood waters reached the confluence of the Mississippi River, most had subsided. Still St. Louis had a series of flash floods from saturated soils, but compared to their upstream neighbors, this was a lucky break.
Snow has also been a significant problem for St. Louis. In fact, the metropolitan area has suffered through a whole variety of winter weather in recent history, from heavy snowfall in 2014, to a blizzard in 2011, to a major ice storm in 2006, all of which caused significant damage. The 2014 snowstorm was estimated to cost the city at least $1 million just for snow removal, for example. The National Guard had to deploy to rescue people across the county in 2011 and delivered emergency services door-to-door to the hundreds of thousands who lost power in 2006.
A history of major snowstorms in St. Louis has not precluded extreme heat days in the summer. Two of the worst heatwaves struck consecutively in 2006 and 2007. First in 2006, heat indexes ranged from 100 to 115 from mid-July to mid-August. To make matters worse, severe thunderstorms caused the worst power outage in St. Louis history, leaving 700,000 buildings without power—some for over a week—in the middle of the heatwave. In total, 794 people had heat-related injuries and eight died across the St. Louis area. Then in August 2007, another heatwave caused the third warmest August on record in St. Louis. In just over a week, 519 people in St. Louis County and 422 people in the city had heat-related injuries, and eight people died. Nearly 500 of the heat injuries were due to attendance at outdoor concerts during the heatwave.
Tornadoes also strike a constant fear in the hearts of the people of St. Louis, especially lately: There have been four significant tornadoes within a three year span in recent history. The first of the tornado events happened in April 2011 when an EF4 tornado touched down in St. Louis County and traveled 21.3 miles. Homes were leveled, the international airport had windows blown out and roof peeled back on the main terminal, but fortunately only five people were injured, and there were no deaths. Nearly 2,500 buildings sustained damage. Two years later in April 2013, two tornadoes hit the St. Louis area and damaged almost 400 homes. This event was followed one month later in May 2013 by another two tornadoes that damaged an additional 600 homes and 100 businesses. Another tornado appeared in April 2014, damaging another 100 buildings.
May 11, 2016: Baseball-size hail at a National Weather Service office in Weldon Spring, Mo.
Source: NWS
The final weather threat facing St. Louis is the most common, and perhaps the most bizarre. Severe weather in this area comes with extreme winds and monster hail, and though it is typically not fatal, it can be costly. St. Louis hail reached 4.5 inches in diameter in May 2011. Imagine grapefruit size blocks of ice being blown down by severe thunderstorm winds onto your roof, car, and windows, breaking or harming everything it its path. In April 2012, two to three inch hail resulted in 150,000 hail damage claims—estimated to cost $995 million—across the state, including St. Louis. In May 2004, 1 inch hail piled up a foot deep and clogged storm drains causing floods on the interstate highways. It also rained hail on a dealership lot full of brand new BMWs and Mercedes Benz. And in 2001, St. Louis had one of its most expensive hail events, estimated to cost several hundred million dollars, after hail 2.75 inches in diameter hit ten thousands of homes and vehicles, damaged every single vehicle at the Ford Motor assembly plant, and harmed 22 jetliners at the international airport and 10 fighter aircrafts at the Missouri National Guard.
