Hi Gino,
I hate to disagree, but although the region is predominantly arid, there are lots of environmental variations in Israel. It's not all desert terrain, and it even snows in some regions. Plenty of opportunities to get muddy/rusty, though I will concede that red mud would be most unusual.
http://dover.idf.il/NR/rdonlyres/30AF0C75-AB8D-4A74-88BC-4DD2210A797B/0/06s_cropped_big.jpg
(oops. Pic is huge so I'll just post the link rather than post the actual pic because it fouls up the formatting of this page and would require scrolling sideways to read the posts.)