At least 20 people were killed in weather-related fatalities this week, including tornadoes that destroyed entire neighborhoods.

Around 73 million people are under flood alerts — including flood advisories, watches and warnings, the later indicating life-threatening flooding is imminent or underway — from Texas to western Pennsylvania, the weather service said. Alerts were likely to remain in place through Sunday morning.

Another round of torrential rain and flash flooding was expected in parts of the South and Midwest already heavily waterlogged by days of relentless severe storms that in some cases spawned deadly tor