Highways England are warning drivers to expect major congestion as they close the M5 in both directions between Burnham-on-Sea and Bridgwater.
They have closed the motorway between Junction 22 and 23 and are working with Weston Power to repair a fallen telegraph pole and over head power lines.
Drivers are being diverted on the A38 until the road is reopened.
Today is expected to be the hottest day of the year, and Highways England are advising people to make sure they bring extra water and plan for the weather conditions.
Bristol Airport have issued a warning to holidaymakers to allow for extra time to get to the airport.