The QEII Bridge at the Dartford Crossing on the M25 has being closed to traffic for safety reasons due to high winds.
Highways England says the bridge, which carries traffic southbound across the Thames, will be reopened as soon as wind speeds drop to a safe level.
Until then, southbound traffic will use one bore of the Dartford Tunnel instead.
The A14 has also been closed crossing the Orwell Bridge in Suffolk because of high winds from Storm Doris.
The diversion route will be clearly signposted via the A1156, A1189 and A1214 through Ipswich.
Highways England is advising road users in the Ipswich area to carefully plan their journeys and consider whether they need to travel around Ipswich during the closure as significant delays will be expected.