Illegal Pot Growers Foiled by Snow-Free Roofs Dutch police ask neighbors to be on the alert By John Johnson, Newser Staff Posted Feb 11, 2015 2:14 PM CST 38 comments Comments The telltale roof near Amsterdam. (Police photo/Twitter) (Newser) – Police near Amsterdam had an easy time of it zeroing in on a suspected marijuana grow house—it was the only one on the block whose roof was clear of snow, reports the Telegraph. Inside the home in Haarlem, cops found the expected heat lamps and pot plants. The trick worked so well that police tweeted out a photo of the telltale roof and asked residents to report any more they see. It's just one of several similar busts, reports the Independent, including one in Amersfoort this week that yielded 500 cannabis plants. “Officers were investigating because the house was completely obscured and the roof was remarkably dry compared to other roofs in the street,” says a police spokesperson. The Netherlands may have relatively liberal marijuana laws when it comes to personal use, but not so much on the cultivation part. It's illegal to have more than five plants per house.