A massive storm system welled up last week in the United States, a nation that consistently has the most violent weather in the world. When we put this show together, there were 90 million people — more than a quarter of the entire U.S. population — who were under the threat of destructive weather. In Texas, Louisiana, and Mississippi, at least five people were killed as the system swept across the south on Saturday and Sunday.

A tornado was spotted in southeast Alabama Sunday morning. And that wasn’t the only threat. A CNN meteorologist said the storms also carried damaging winds and hail. The National Weather Service warned people in the path that torrential rains could cause flash flooding in some areas. Monroe County, in northeast Mississippi, was hit particularly hard, according to its sheriff. He said the area was a mess, after homes, businesses and a fire station were destroyed. There was also a lot of flooding there.

And two states east, in Georgia, tee times were scheduled earlier for The Masters Golf Tournament on Sunday, because heavy storms were expected to pass through later that night. In fact, a tornado watch was issued for the city of Augusta, as well as parts of South Carolina Sunday night. Knowing the difference between a watch and a warning can help you know what action you should take.