Two views from my kitchen window. On an average day I can see across the field and beyond. A few days ago I saw the snow storm coming across the field. The snow was so thick that you could not tell where the ground ended and the sky began. Seconds later you could not see the pole, a mere 30 ft away.

Many times during the winter, we will hear traffic reports advising of zero visibility due to snow. Imagine driving in this - you just cannot see the road or other vehicles and it happens in seconds with no warning.