Well, he plunked the car against a wall in the tunel back in 04, when he was runing second and trying to catch his team-mate (not gonna happen since jarno was faster) and he crashed again against Heidfeld in 2008 (entirely his fault and by the way, it was raining again!) ...and yes, that crash during practice also counts, counts so much that probably costed him the title that year.
You seriously count messing up his front wing in 2008 as a crash? Whatever, anyway: -I forgot about Nurburgring 2007 which was another stellar victory in sopping wet and changing conditions -Korea 2010 when he won in a deluge -Silverstone 2011 which was another win in changing conditions. -Hungary 2006 which he started 15th after being penalized two seconds for overtaking under yellows in Friday practice. Alonso got to 7th place in the first lap in soaking wet conditions before eventually passing none other than MS on the OUTSIDE IN THE WET and making his way to the lead. His wheel flew off while he was leading easily. You could make a strong case for Alonso being the best rain driver in the field at the moment.
You could but still it wouldn't be true since in 07 there was a guy with the same car that was able to show a lot better pace in the wet...and there is another one that showed he was even better the folowing year...so i would easily rank vettel first in the wet folowed by Hamilton...and Button is no slouch either.