Drivers were caught by flash flooding on the M25 after “biblical rain and hail” fell in the UK.
One onlooker said that more than 20 cars looked as if they were stranded and that the water was feet-high in some areas.
Another road user tweeted: “M25 flooded near Junction 7. Biblical rain and hail. Clockwise traffic at a standstill.”
Surrey Police said the motorway remains closed due to the flooding.
The force said Highways England had managed to pump enough water to allow the hard shoulder to reopen for trapped vehicles.
One Twitter user said: “3 hours so far on M25 closed due to flooding and drains blocked.”
Video also emerged showing water flowing down a street and around car wheels in Croydon.
The Met Office has issued yellow thunderstorm warnings for the next five days, with the potential of flash flooding or damage to buildings from lightning and hail.
Warnings of further unsettled weather follow stormy scenes across parts of the country since Tuesday, amid sweltering conditions and “tropical nights”, where after-dark temperatures do not fall below 20C.
Forecasters have also warned of potential damage to buildings from lightning strikes or strong winds and a chance of travel disruption due to flooding.
Chief meteorologist Paul Gundersen said the hot weather has created ideal conditions for thunderstorms.
“The storms will be isolated but where they happen there will be frequent lightning, gusty winds and intense, heavy downpours with 30 to 40mm of rain possible in less than an hour and, in isolated spots, a small chance of 60mm falling.
“With the continuing hot weather large swathes of the UK continue to be at risk from thunderstorms and potentially the impacts from heavy rain, into the early part of next week.”