A while ago my server had a sudden ICE AGE, not jokes or trickery here, all water on my server just started to freeze up! I posted about it in the forums and some people didn't even believe me ( but also some people did, thankfully)
so I'm uploading some pictures here so people can see!

Thankfully though I got it sorted and everything went back to normal, a little bit of the /Thaw command from worldGuard plugin and the No Ice plugin everything is now flowing properly (s'cuse the pun ;) )

here is the NO ICE plugin,
http://forums.bukkit.org/threads/mech-fix-noice-v1-2-stop-that-pesky-ice-1060.23620/
(Stops ice spawning/forming but doesn't get rid of existing ice)

Here is the WorldGuard plugin
http://forums.bukkit.org/threads/sec-worldguard-5-2-block-fire-ice-melt-mushrooms-advanced-fast-area-protect-blacklist-1000.790/
(Helpful for editing, and has the /thaw command to get rid of that ice you don't want!)

Cheers for reading, hope this never happens to you! ;P
--Rhee