The Boardmasters festival has been cancelled amid severe storm forecasts - hours before gates were due to open.
The event - headlined by Wu-Tang Clan, Florence + The Machine and Foals - was due to host 55,000 people near Newquay. Organisers said on Tuesday night they were cancelling after speaking to police ahead of strong winds forecasted for Cornwall on Friday and Saturday.
Although the main acts were not on until Friday, gates were due to open on Wednesday. The Met Office has issued a yellow weather warning for heavy rain and thunderstorms for much of England and Wales on Friday and Saturday and said Cornwall faced strong winds.
Crowds of people are queuing at Newquay's railway station, waiting to find out where to go next. All campsites in the town are full and people are being directed to campsites on the outskirts of the town if they wish to stay, tourism bosses said.
A statement from Boardmasters organisers, posted at about 23:10 BST on Tuesday, said: "The safety of you, the fans and attendees, as well as performers and crew comes first, and the potential risk is too severe for the event to go ahead at this time." Refund information will be shared "as soon as possible", they added.
Ticket holders Charlotte-Louise Summers and Hannah O'Brien said they understood the decision but wished organisers "gave more notice"
Ticket prices ranged from £69 for day-entry passes through to VIP packages for five days of camping from about £370 per person.
The three-day event attended by 55,000 people last year was being held at Watergate Bay and festivalgoers had been already making their way to Newquay. The five-day surfing side of event, due to start at nearby Fistral beach later, is still due to go ahead.
I feel sorry for the kids who have been looking forward to it.
I was just thinking that 30-odd years ago when I started going to festivals, it would have been impossible to call it off the evening before as nobody would know - there was no social media etc. in those days! People would have just carried on turning up!
My daughter went last year and really enjoyed it.I feel sorry for the kids who have been looking forward to it.I was just thinking that 30-odd years ago when I started going to festivals, it would have been impossible to call it off the evening befor