At least 20 people have died from flash flooding and tornado damage that swept across multiple states in the the midwestern and southern parts of the US over the weekend.

Half of the reported deaths, which included children and elderly people were in Tennessee, and three were in Missouri. Two people died in Kentucky while Indiana, Mississippi, Georgia and Arkansas have also reported deaths from the storm.

The fierce weather has caused rivers to swell and on Sunday, the National Weather Service warned that dozens of locations would reach ?major flood stage? even as the rain slow.

The storm is expected to move towards the southeast Atlantic coast on Monday.

In Kentucky, a 9-year-old boy was swept away by floodwaters while walking to his school bus stop. His body was found two hours later.

In Missouri, 16-year-old volunteer firefighter Chevy Gall died in a crash while trying to rescue people caught in the storm.

?Chevy died while answering the call to help others,? said local Fire Chief Terry Feth.

?Our entire department is grieving, as we mourn with Chevy?s family, friends, and our fellow first responders during this incredibly difficult time.?

In Little Rock, Arkansas, a 5-year-old boy was killed by a tree that fell into his home, destroying it.

In Georgia, a father and son were both killed on Sunday while playing golf. According to a coroner?s report, Matthew Terrell Collins Sr, 58, and Matthew Terrell Collins Jr, 29, died when a tree fell on their golf cart.

A GoFundMe started to raise money for the Collins family described: ?They were spending time together when the storm struck ? sharing a moment between father and son that would unknowingly become their last.?

More than nine million people are under a flood watch as of Monday morning, according to NBC News.

Swollen rivers are threatening to overthrow and swamp cities such as Frankfort, Kentucky, prompting mandatory evacuations in some areas.

?As long as I?ve been alive ? and I?m 52 ? this is the worst I?ve ever seen it,? Frankfort resident Wendy Quire told AP News on Sunday.

?The rain just won?t stop,? she added. ?It?s been nonstop for days and days.?

On Monday, the storm is expected to push towards the coast, bringing potentially severe rainfall to Florida, Georgia and the Carolinas.

The Augusta National Golf Club, currently hosting the high-profile Masters Tournament, was forced to evacuate on Monday morning.

It has been a punishing week of weather for the Midwest. Dozens of tornados have been reported and hundreds of counties have spent days under storm warnings since Wednesday.

The same region was hit by tornadoes, wildfires and dust storms that killed 40 and left ?staggering? damage in March. (BBC: Text, Excluding Headline)

Update news