Thundersnow

We were sitting in a coffee shop on Reykjavik's main street last week, when there was a flash of light that we all assumed was a camera flash. But then came the unmistakable sound of thunder. The air temperature was a couple of degrees above freezing and a mix of rain and sleet was falling. It turns out that this is one of the rarer meteorological phenomena - thundersnow. Read more about it here: http://www.straightdope.com/columns/read/2196/why-dont-snowstorms-produce-lightning