In the Netherlands this winter, police unveiled their latest method for detecting illegal indoor pot gardens: they look for rooftops with melted snow.
Earlier this month police raided a residence in Haarlem, a city west of Amsterdam, after noticing its roof was the only one on the block not covered in snow. The bare roof suggested to cops that the apartment contained an abnormal number of lights, which produced enough heat to melt the snow. That was all the probable cause necessary to raid the house. Once inside, officers discovered the snow-melting heat lamps used on an industrial scale to cultivate an undisclosed number of plants.
Police even tweeted a pic of the snow-less Haarlem roof to warn other growers.
Previously, conspicuously absent rooftop snow lead cops to a residence in the town of Zutphen where they found 88 plants. Dutch citizens are only permitted to grow up to five pot plants at any time.