Worst snow I've fished a match in was around 1990 on the Oxford Canal at Kidlington. Left Uxbridge on a lovely clear frosty morning, got through the cutting on the M40 at Stokenchurch and straight into a blizzard. After a quick consultation with my mate (the driver) we decided to keep going as we were past halfway. Hard work finding our pegs as already 2 or 3 inches of snow on the towpath and it kept getting heavier with those big wet flakes coming down all day; ended up with a drift at least 18 inches deep against the side of my brolly, had a brollyless Mick Vincent next to me who called it a day after three hours of increasingly resembling a snowman .
Finished with 4lb odd of gudgeon for either last in the frame or a section win, cant remember which. Mate had his section as well so back to the pub for the brown envelopes, to be asked straightaway by the landlord where we had to get back to. Apparently the snow had been so bad a bit further north that there was some doubt whether those who had come down from Coventry/ anywhere North of Banbury were going to be able to get home,,,
As Mick said earlier, have sea fished in worse. Remember an all nighter in a blizzard on Blyth Pier in Northumberland, had a big sheet of polythene tied between and along the railings on either side for a shelter, not a sound apart from the occasional foghorn, just watching the rod tips nod in the swell against a background that looked like one of those snowshakers. Was well worth it for the half dozen codling up to 5lb.
Wouldn't do it now though