The A259 in Littlehampton is blocked due to a fallen tree, causing gridlock this morning (December 9).
According to traffic reports, it is affecting traffic in both directions between Church Lane and Bridge Road, with queues to Wick and the outskirts of Bognor Regis.
Some smaller vehicles are said to be mounting the pavement to get past.
The accident is also causing delays on A284 Lyminster Road northbound between the A259 and A27 Crossbush Junction.
On Facebook, Tina Jones said: "Saw a bloke pulling bits of tree out from under his car, must have fallen just in front of him."
This comes as the Met Office has issued a yellow weather warning for wind for much of the south coast, which is due to end at 9am today.