Torrential rain has caused flooding at schools, hospitals and roads in north Wales.
A yellow “be aware” weather warning issued by the Met Office is in place until 22:00 BST.
Police are warning motorists to take care on flooded roads and a number of buildings have been closed to the public.
Water was pouring into theatres at Abergele Hospital, but the health board said patients were not affected.
A video on social media shows water cascading down a stairwell at the hospital, managed by Betsi Cadwaladr University Health Board.
Meanwhile, a lightning strike on a Gwynedd pub earlier on Wednesday caused a fire to a chimney stack.
Crews were called to the Peniarth Arms in Bryncrug, near Tywyn, and the fire was put out at 03:30 BST. North Wales Fire and Rescue Service said there were no injuries.
Alex Jones, in Rhyl, tweeted that many roads had “turned to rivers” after torrential rain, with “drains going up like fountains”.
The Met Office said about 30mm (1.2in) of rain could fall in an hour causing a “chance” of localised flooding while lightning and hail could lead to disruption of power networks.
Motorists in north Wales are urged by police to take care because of heavy rain, and walkers are advised to take wellies.
Supt Rob Kirman tweeted: “Please slow down & turn your lights on if you’re driving in the rain. Currently very heavy in central part of North Wales.”
The force said affected areas include the A55, near Rainbow Bridge, Colwyn Bay.
There are also reports of very slow traffic due to flooding on the A547 in both directions, in Denbighshire, affecting traffic between Rhuddlan and Prestatyn.
Roads in Rhuddlan have been described as being “impassable”.
Prestatyn High School and Ysgol Clawdd Offa will be closed on Thursday due to severe flooding, Denbighshire Council confirmed.
Lisa Jones, whose three children go to the school, said there was damage to some of the classrooms and the town was “totally flooded at the bottom of the high street”.
She said she had no idea if pupils would now go back to school before the summer break, saying: “It is a bit of a mess”.
Denbighshire council said it had seen an increase in the number of calls late Wednesday afternoon as a result of storms affecting northern parts of the county.
Prestatyn Leisure Centre has been closed due to flood damage, while the council closed parts of Rhyl Leisure Centre and the Nova centre, Prestatyn as the storms on the coast caused water to enter the buildings via the roof and up through the floor.
North Wales Bowls Centre has also been affected by flooding.
A council spokesman said staff were working with colleagues from the emergency services to respond to the situation and would monitor weather forecasts for the latest updates.
A yellow warning is the lowest level, rising in severity through amber to red for the most severe weather.