Oklahoma tornado impacts flights

Severe weather and tornadoes are affecting travel to Oklahoma City.

Airlines are advising passengers to regularly check their flight status for updates to their flight plans.

Delta has confirmed that if a flight is cancelled or significantly delayed, passengers are entitled to a refund. Even if a flight is not cancelled, passengers may make a one-time change to their ticket without a change fee if they are scheduled to travel to, from or through Oklahoma City. Delta passengers can also have up-to-the-minute info about their flight plans send directly to a wireless device or email with Delta Messenger.

It has been reported that the tornado was at least three kilometres wide in places and had winds of up to 320kph. The National Weather Service assigned the twister a preliminary ranking of EF4 on the Enhanced Fujita Scale, meaning the second most powerful category of tornado.

Severe weather was expected through the night from the Great Lakes south to Texas.