The disaster situation means that federal resources can be deployed in relief work after the storm. A White House statement stresses, among other things, the need for temporary housing, repairs and loans to support affected individuals and businesses in the region.
"We will do everything we can to help. We will work together to deliver the support you need to recover, no matter how long it takes," the president wrote on Twitter on Saturday.
Risk of new tornadoes
So far, 25 deaths have been reported as a result of the storm in Mississippi, local authorities said. Another death has been recorded in neighboring Alabama, where a man died after his residence — a so-called caravan — was swept along by the wind. The number of injured after the storm is counted in the dozens.
However, the ongoing work of searching through razed buildings looks set to run into problems. The U.S. National Weather Service has warned of continued storms through Sunday with high winds, hail and the risk of new tornadoes.
'Very very rare'
Preliminary data from the National Weather Service shows that the tornado that pulled through the Mississippi on Friday at times reached a wind force between 265 and 320 kilometers per hour, the AP writes.
However, the explanation for the extensive damage lies largely in its longevity. The authority estimates that the tornado swept over a distance over 27 miles and was active for over an hour.
"It's rare. Very, very rare," Lance Perrilloux, a meteorologist with the National Weather Service told the AP.