Hasn't happened to me yet (fingers crossed). In the thread that veilo linked to, there was one post that quoted a possible solution:
Got those giant shards and artifacts making the game unplayable? Fix is here:
Go to Documents/ArmA 2/playername.ArmaA2OAProfile
Open file in Notepad
Search for "sceneComplexity=;"
Change to "sceneComplexity=100000;"
Save changes and exit.
Launch DayZ with preferred method.
edit: The one below seems like the dunny solution:
press dash on number pad once
will fix it for the time being. do the same if you see it again
Note, I haven't tried these as I haven't had the problem, no idea if they work.