In the meantime, moist air from the Gulf of Mexico moved into the Midwestern United States through the Mississippi River valley as a second Canadian high-pressure system arrived from the west, creating a low-pressure trough that stretched from southern Illinois, across central Indiana, and into northern Ohio.

Major tornadoes hit Omaha, Nebraska; Lone Peach, Arkansas; and Terre Haute, Indiana.

On Monday and Tuesday, March 24 and 25, 3 to 8 inches (76 to 203 mm) of rain fell in Ohio, Indiana, and southern Illinois.

On Wednesday, March 26, the storm moved east into Pennsylvania and New York, while heavy rain continued in the Ohio River valley.

Ohio governor James M. Cox called on the state legislature to appropriate $250,000 ($7.71 million in 2023 dollars) for emergency aid.

Many communities cared for their own flood victims with Red Cross assistance, charitable donations, and contributions from local businesses, industries, and service organizations.

[2] Storm-related flooding affected more than a dozen states: Alabama, Arkansas, Connecticut, Illinois, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Vermont, and Virginia.

The same weather system caused major tornadoes in the Great Plains, the South, and the Midwest, most notably in Omaha, Nebraska; Lone Peach, Arkansas; and Terre Haute, Indiana.

[1][3][4][5][6][7] Between March 23 and 25, heavy rains and rising waters from the Great Miami River burst levees on Dayton's south side and flooded 14 square miles (36 km2) of the city.

[8] On March 26, as floodwaters reached their crest, Dayton's business district suffered more damage after an early morning fire and gas explosion.

Downstream in nearby Hamilton, Ohio, about 100 people died after water 10 to 18 feet (3.0 to 5.5 m) deep flowed into its residential neighborhoods.

[11][12][13][14] On March 26, floodwaters estimated at 19.5 feet (5.9 m) above flood stage destroyed Indianapolis's Washington Street bridge, the main connection over the White River.

[15][16] The city's transportation and water supply were disrupted for nearly four days in flooded areas and as many as 7,000 Indianapolis families lost their homes.

As moist air from the Gulf of Mexico moved into the Midwest through the Mississippi River valley, a second Canadian high-pressure system arrived from the west and squeezed the low into a trough that stretched from southern Illinois, across central Indiana, and into northern Ohio.

[17] Louisville, Kentucky, experienced the storm's heaviest recorded rainfall rate of 1.05 inches (27 mm) in twenty-eight minutes on March 25.

High waters continued to flow south to the Gulf of Mexico, causing some levees to fail in Arkansas, Kentucky, Louisiana, Mississippi, and Missouri.

Theaters around the country were showing pictures of the flood devastation in Dayton and other Ohio cities and tornado damage in Omaha, Nebraska, within weeks after the disaster.

[35] The American Red Cross was still a small organization in March 1913, with a few full-time employees at its headquarters in Washington, D.C. and about sixty volunteer chapters in the United States, when President Woodrow Wilson named it "the official disaster-relief agency for the federal government".

[35][36] Flood reports in the country's newspapers carried an appeal from the president to help victims with contributions to the Red Cross.

Indiana governor Samuel M. Ralston did not receive President Wilson's telegram offering federal support due to flood-damaged communications.

Red Cross disaster relief in other regions of the United States, with the exception of Omaha, Nebraska, and Lower Peach Tree, Alabama, was limited or nonexistent.

[35][38] Governor Cox called on the Ohio legislature to appropriate $250,000 ($7.71 million in 2023 dollars) for emergency aid and declared a 10-day bank holiday.

[39] Governor Ralston appealed to Indiana cities and other states for relief assistance and donations of money and supplies.

Railroads, most notably "the Big Four, the Pennsylvania Lines, and the Vandalia," put their equipment at the Indiana governor's disposal and had work crews rebuild the state's rail network.

[35] The Chicago Association of Commerce wired $100,000 to the Red Cross on March 26, becoming one of many organizations that contributed funds for flood relief.

[38] Flood deaths in Ohio, Indiana, and eleven other states (Arkansas, Illinois, Kentucky, Louisiana, Maryland, Michigan, Missouri, New York, Pennsylvania, West Virginia, and Wisconsin)[44] are estimated at approximately 650.

[30][38] Dayton's official death toll was not certain, but Ohio's Bureau of Statistics listed eighty-two people, while one flood historian puts the number at ninety-eight.

Flooding stopped communications between Chicago and New York for a day and a half, disrupted road and rail transportation, and slowed mail delivery.