How high is this surf?

This surf wave shown above, reported in U.K.'s DailyMail, is described as 50 feet high. But a number of readers of the article think that wave is clearly not 50 feet high with their estimate varied between 15 and 30 feet.

On the other hand Telegraph reports the same wave as 30 feet along with a video.  Take a look at the pictures and the video, how would you estimate the size of this surf?

By the way this wave happened at U.K.'s famous Fistral Beach near Newquay in Cornwall.  The locals called this wave case as a phenomenon known to be the 'Cribbar', which is named after a reef located at the north end of the beach.  According to Chris Slack, author of the Daily Mail article: "They occur just once every 18 months when conditions involving the Atlantic swells and the onshore winds combine to cause the perfect surf conditions."  Now I am very much wondering how did they came up with this "18 months" number or what kind of data they have that led to this contention?  If they have data that documents this phenomena, it should worth some scientists' time to take a detailed look at it!


P.S.  

I have actually blogged about U.K.'s Cribbar once before here.