If it felt like the rain just wouldn't stop across the Midwest this week, there's a reason—and the numbers prove it. A relentless weather pattern has dumped staggering amounts of rain across the region, triggering catastrophic, record-breaking flooding.

Indiana bore the brunt of the deluge, with widespread rainfall totals topping 12 inches in towns like Modoc (12.12") and Winamac (12.11"), nearly 12 inches in New Castle (11.80"), and 10.40 inches in Anderson.

The massive runoff drove unprecedented river flooding. In Anderson, Indiana, the White River crested at a historic 24.93 feet on Friday, Aug. 14, shattering the city's previous all-time flood record of 23.6 feet set over a century ago during the Great Flood of 1913.

Weather in your inbox

Forecast Location

Sign Up

By signing up you agree to the Terms & Privacy Policy. Unsubscribe at any time.

Surrounding Midwest states were hit hard as well, with storm totals exceeding 6 inches across parts of Illinois and Iowa.

A stalled front sets the stage

It all starts with a frontal boundary that essentially hit the brakes across the Midwest. Instead of sweeping through, the front lingered over the same general area. This gave storms a pathway to repeatedly develop and move across places like Indiana.

Think of a stalled front like the front of a car boxed in — hot, humid air pressing in from the south and cooler air to the north kept it parked over the same area. 

Get More of Our News on Google

Set The Weather Company as a 'Preferred Source' to get quicker access to the news you value.

A conveyor belt of Gulf moisture

But storms need moisture and there was plenty of it. A high pressure system over the Gulf helped funnel warm, humid air —acting as a conveyor belt of moisture aimed toward the stalled front. 

Every new disturbance moving into the Midwest taps into that tropical moisture pipeline, producing round after round of heavy rain over soaked ground. These triggers don't need to be major storms. Even a small ripple in the jet stream riding around the heat dome is enough to set off another severe deluge.

Earlier rounds of rain this month had already saturated the ground, priming the region for even worse flooding when the next deluges arrived. 

And there was another reason this moisture-rich pattern was so hard to budge: a stubborn heat dome anchored in the South.

A stubborn southern heat dome

You’ve probably heard the term heat dome a lot lately. This stubborn area of upper-level high pressure has parked itself over multiple parts of the U.S. this summer and now it’s settled over the South. 

Think of it like a traffic jam in the atmosphere. With the heat dome holding firm in the South, the larger pattern had little room to shift and kept the Midwest stuck in the path of repeated storms. 

Faiza Mohammed is a meteorologist intern at weather.com. She studied geography and worked with the Weather Dawgs team at the University of Georgia. She also received her master's in Earth and Atmospheric Sciences from the Georgia Institute of Technology.