On Valentine's Day (February 14, 2013), convective snow showers developed over northeastern Wyoming and western South Dakota. Convective snow showers are typically characterized by rapidly changing conditions on the ground due to rapid changes in snow shower intensity. The visibility can be greater than 10 miles one minute. Then, the visibility can drop to less than a mile the next minute. View the snow streaks the next day.
Here is what the radar looked like at 218 PM MST February 14, 2013.
At about the same check, observe the bumpy nature of the clouds via the 1km Visible Image below.
The environment conducive for snow showers were the result of steep low level lapse rates noted in the sounding below. Lapse rate is the change of temperature with height.
The next day (February 15, 2013), the visible satellite image revealed several streaks of accumulating snow from yesterday's convective snow showers.