ST. LOUIS COUNTY, Mo. — "It is one of the more deadly phenomena we predict around here," National Weather Service Hydrologist Mark Fuchs said.
He's talking about flash flooding, like what Columbia, Missouri, experienced Friday morning and again in the evening. Torrential rainfall resulted in widespread flash flooding.
"Flash flooding is, by definition, flooding that occurs in an area within six hours or so of the heavy rain event," Fuchs explained.
During thunderstorms and periods of heavy rain like the St. Louis area is currently expecting, rivers like the Meramec, Missouri and Mississippi are not the main concern. Streams and creeks are the ones that rise rapidly, surging out of their banks.
Deputy Chief Kelly Grassmuck of West County EMS & Fire Protection District said because of the forecast, his swift water team is on standby.
"Flash flooding is a lot different than the river issues and the drownings we've been dealing with here lately," he said. "Flash flooding is probably a little bit more dangerous, just because it catches people by surprise."
Grassmuck wants people to be aware of the forecast and plan their traveling accordingly.
"If you're familiar with your route and you know that it's something that normally floods, slow down, take your time. If you encounter high water, water over the road just don't drive into it," he said.
Even if recent storms haven't caused issues yet, upcoming ones certainly might.
"The further north you go, the more saturated it is and the higher the risk," Fuchs said. "There's not that room in the soil to act as a sponge."
Flash flooding will not be the only issue to watch for; rising rivers, especially the Missouri, will result in debris flow, hidden obstacles and dangerous currents.