imo, there's a little bit of a puzzle about why there wasn't snow coverage on the pavement. the snow had fallen, and there was a thin blanket on non-pavement. it would have fallen on the pavement too! and the temperature had never come above freezing (or even close) during the night, so it shouldn't have melted.
i suspect it was a very light, powdery snow, and it just sat on the pavement rather than "sticking" like they were in wet contact. both of those are things that tend to happen when the temperature is double digits below freezing, as it was. and, if that's the case, it could have blown and "drifted" off to the sides of the pavement. piled up against the edge of the grass, etc. even if the average wind speed had been low that night, i think even the slightest breeze could have swept aside a thin layer of powder snow. my guess is that's what happened.
i suspect it was a very light, powdery snow, and it just sat on the pavement rather than "sticking" like they were in wet contact. both of those are things that tend to happen when the temperature is double digits below freezing, as it was. and, if that's the case, it could have blown and "drifted" off to the sides of the pavement. piled up against the edge of the grass, etc. even if the average wind speed had been low that night, i think even the slightest breeze could have swept aside a thin layer of powder snow. my guess is that's what happened.
