The worst storms to slam southern US states in years flattened buildings and overturned vehicles, with intense tornados and floods leaving a trail of destruction and 190 people dead

The worst storms to slam southern US states in years flattened buildings and overturned vehicles, with intense tornados and floods leaving a trail of destruction and 190 people dead.
  
The severe weather killed 128 people in Alabama on Wednesday alone, authorities said, and President Barack Obama said Washington would be rushing assistance to the battered southeastern state.
  
States of emergency were declared in Alabama, Arkansas, Georgia, Kentucky, Mississippi, Missouri, Tennessee and Oklahoma, and governors called out the National Guard to help with rescue and cleanup operations.
 
The National Weather Service (NWS) had preliminary reports of more than 300 tornados since storms began Friday, including more than 130 on Wednesday alone.

The Tuesday-Wednesday storms are believed to be the deadliest US natural disaster since Hurricane Katrina of 2005, and Accuweather.com said the tornados were the worst since 310 people were killed on April 3, 1974.
  
The NWS issued a rare "high-risk" warning of tornados, hail, flash flooding and dangerous lightning for parts of Alabama, Georgia and Mississippi. It warned that severe weather could also strike 21 states from the Great Lakes down to the Gulf Coast and across to the Atlantic, and tornados were reported as far east as Virginia and Maryland.

The death toll was set to rise as skies are not expected to clear until late Thursday or Friday, and there will be little time to mop up, as another major storm system is forecast to bring heavy rain and high winds on Saturday.