AA Traffic Maps says there is severe delays and one lane closed due to debris on road and stalled crane on M5 Southbound from J13 A419 (Stroud) to J14 B4509 (Thornbury / Falfield).
It says this was previously reported to them as an accident.
National Highway says that there are 45 minute delays and 4 miles of congestion on the approach.
Specialist recovery has been requested, it adds.
Meanwhile the M5 is blocked and has severe delays at the M5 Southbound from J17 A4018 (Cribbs Causeway) to J18 M49 (Aztec West) due to a multi-vehicle crash, reports the AA Traffic Maps.
It adds that traffic is also heavy on the opposite side due to onlookers.
An Avon and Somerset Police spokesperson said: “The M5 Southbound carriageway is closed between junction 17 (Cribbs Causeway) and junction 18 (Avonmouth) following a multi-vehicle collision this afternoon (Wednesday 27 May).
“Emergency services are on the scene and thankfully we believe no one is thought to be seriously hurt.
“Motorists are advised to please be patient as work is underway to clear the carriageway as quickly as possible.”
