Portland is hosting a major training exercise that will involve the simulated crash of a jet at the Portland International Jetport.

The disaster drill will be held from 9 a.m. to 3 p.m. today. During that time, the northbound lanes of the Veterans Memorial Bridge from South Portland to the Fore River Parkway will be closed.

Drivers should expect delays and many emergency vehicles on the Fore River Parkway and Commercial Street in Portland.

The scenario for the drill, which is a required exercise, is the crash of an inbound plane into the Fore River south of the Veterans Memorial Bridge.