© BILLS GREEN/WEATHERWATCHERSParticularly hard-hit by the hail were Guiseley, Baildon and Otley
The storms, which began at about 16:00 BST, battered much of the region with lightning continuing for several hours.
Hail was reportedly up to 2.5cm (1in) in diameter in places, making conditions difficult for drivers.
A supercell is a severe variety of thunderstorm caused by a change in wind speed and direction.
BBC Weather forecaster Billy Payne said: "We don't see supercells all too often in the UK - they are more commonly seen in the United States Great Plains where they can produce powerful tornadoes and large hail at times."
People living in Baildon, Guiseley, Otley and Menston, shared images on social media of the flash storms leaving them in several centimetres of hail.
Fork lightning was also captured in Leeds, Knaresborough, and in Bridlington and along the east coast of Yorkshire.
BBC Look North presenter Charlotte Leeming, who lives near Leeds, said she had never experienced a storm like it, as "the house shook with thunder and the roads were carpets of white".
Lesley Potter, who lives in Baildon near Bradford, said: "It was horrendous and I have never experienced a hailstorm as bad, coinciding with thunder and lightning".
Mr Payne added the UK had seen a "real transition" into autumn over the past few days, with Atlantic low pressure systems sweeping away the warm temperatures from the start of the week.
"The last 24 hours in particular we've seen an area of low pressure tracking to the south of climatology over the southern half of the UK, bringing something much more unsettled and locally disruptive," he said.
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