The National Weather Service has urged the public to stay safe in the excessive heat.
There are fire warnings in western U.S. states.
One Twitter user commented that a dock was floating down Lake Wylie River
The vast Mississippi River—the second longest river in North America—swirls through a number of U.S. states and has been swelling in recent weeks. That may continue, experts say.
"The world must be coming to an end," one scientist joked.
An "atmospheric river" has been fueling the storm.
The slow-moving system has already dropped large hail and inches of rainfall in parts of Texas and Missouri.
Temperatures across the northeastern U.S. are expected to be 20 to 30 degrees Fahrenheit below average this weekend.
This would be the second coldest New Year's Eve in New York City if the temperature drops as forecasted.
The storm has surpassed the standard precipitation map capabilities.