Further north, a winter of severe weather stretched into the second day of spring as a storm bore down on the Midwest, dropping heavy snow and delaying flights.

Many rivers were swollen beyond their banks, leaving houses under water, from parts of Texas north to Ohio after inundating rains this week - in some cases on the heels of record snowstorms earlier in the month that left soils saturated.

Reports across the region said some 16 people had died, either swept away by rushing waters or in traffic accidents blamed on the heavy storms.

Traffic was being held to one lane on Interstate 44 west of St Louis, as workers frantically sandbagged against advancing waters on the Meramec River in Missouri.

The Missouri Department of Transportation showed dozens of roads closed by floods across the southern one-third of the state. Parts of the state received upwards of 10 inches of rain this week.

Flights at Chicago's O'Hare International Airport were already subject to lengthy ground delays, according to the Federal Aviation Administration's Website. Some flights arriving at O'Hare were being delayed by more than three hours.