It's why they declare a snow emergency hours before the first hint of snow, or when the prediction is for barely noticeable accumulation.

Actually, there's a policy for that: if 4 or more inches are predicted, a snow emergency is called (every time). So, when I see 4 or more inches predicted in the morning, or the night before, I go ahead and move my car.

Hopefully, this will help you in the next snow emergency.