The deadly tornadoes ripped through seven states, obliterating entire towns in some cases. This is the worst tornado devastation in 80 years.
At least 342 people died across seven states, including 250 in Alabama. Thousands more were injured.
Search operations continue for the missing, and curfews are in force to prevent looting. Thousands of homes are still without power.
Seeking to speed recovery, Homeland Security Secretary Janet Napolitano and other Cabinet members toured the debris-littered landscape in Alabama and Mississippi later Sunday. President Barack Obama, who visited Alabama on Friday, already has signed disaster declarations for those two states and Georgia.
Also, the Red Cross has opened emergency shelters and the task for authorities of finding more permanent housing for the thousands without homes begins this week.
Authorities also are seeking the missing, aided by cadaver-sniffing dogs, amid fears the death toll could yet rise.
Residents in several states continue to pick up the pieces following one of the deadliest tornado outbreaks in recent history.
The latest weather marks the most ravaging tornado destruction in the U.S. since 1925.
Hundreds of people remained missing Sunday. About 500,000 people in Alabama were without power, and were not expected to have power restored until the end of the week. Survivors of the storm are turning to the federal government as well as friends and neighbors.
About 2,000 people live in Sawyerville, Ala., about 60 miles from Tuscaloosa. Six people in the town died.
The Sawyerville Fire Station has been turned into an aid station.
Local resident Angie Crawford wanted to get a message out to her brother in Los Angeles: "I'll tell him, keep praying for us. Some people got hit and we are doing good, but some of us, not."
As hundreds of people in the region are still unaccounted for, the death toll continued to rise.
In many cases, people reportedly had as much as 24 minutes of warning before the tornadoes struck.
One destroyed structure had been built from cinderblocks with a brick exterior, a very sturdy build. That structure was completely leveled by one tornado, demonstrating its destructive force.
As Alabama and neighboring states struggle to dig out of the second-worst tornado disaster in American history, representatives from the Federal Emergency Management Agency (FEMA) were out in force, eager to wipe away the shame of the response to Hurricane Katrina.
Business owner Steve Acker was happy with the government response. "Very much so. And more than that, just the people themselves. The volunteers got started almost immediately after this disaster," said Acker.
The Alabama governor called for a statewide day of prayer. In the face of so much loss, the people of the state haven't lost their faith.
FEMA declared the tornado swarm a Category 1 federal disaster, on the same level as Hurricane Katrina and 9/11 and has responded accordingly. An 8 p.m. curfew was in place Sunday.
Tuscaloosa Mayor Walt Maddox said late Saturday that 434 people were unaccounted for, down from 570 hours earlier.
Maddox said the storms had damaged more than 5,700 buildings and homes in the Tuscaloosa area alone. Mississippi emergency officials said its latest survey showed damage to more than 2,500 homes and 100 businesses there. Virginia officials reported that last week's storms damaged about 500 structures in five counties, destroying 55.
Eyewitness News anchor Marc Brown is in the Tuscaloosa tornado zone. You can watch his live reports on Eyewitness News.
The Associated Press contributed to this report.