The 1916 Hatfield Flood of San Diego, California, destroyed the Sweetwater and Lower Otay Dams, and caused 22 deaths and $4.5 million in damages
. The Vermont flood of 1927 is probably the worst flood in Vermont history doing $30 million in damages, which would be $270 million today, killed over 83 people and left 9,000 homeless.
The Ohio River flood of 1937 took place in late January and February 1937. With damage stretching from Pittsburgh to Cairo, Illinois, one million were left homeless, with 385 dead and property losses reaching $500 million. In 1957, storm surge flooding from Hurricane Audrey killed about 400 people in southwest Louisiana.
In 1965, Hurricane Betsy flooded large areas of New Orleans, Louisiana, for up to 10 days, drowning around 40 people.
In 1972, the Black Hills flood killed 238 people and caused $160 million of damage in western South Dakota.
In 1983, the Pacific Northwest saw one of their worst winter floods, And some of the Northwest states saw their wettest winter yet. The damage was estimated at $1.1 billion.
In Alaska from May to September 1992 unusually wet conditions, plus snow melt, caused the 100 year flood in areas of Alaska.
The Great Flood of 1993 was one of the most destructive floods in United States history.
On 8 May 1995, a flood hit Louisiana and caused extensive damage.
The Red River Flood of 1997 occurred in April and May 1997 along the Red River of the North in North Dakota, Minnesota, and Manitoba (Canada). It was the most severe flooding of the river since 1826.
So where does this one rank?
You left out The Great Mississippi Flood of 1927.
With 27,000 square miles inundated up to a depth of 30 feet.