Bad day to drive

I spent most of Tuesday in the car, and my traveling companions were snow and a bit of freezing rain. But I have been in worse. Which prompts me to ask, what is the worst weather you have ever driven in? I will give you my answer sometime in the future, when I have a slow day.
Despite the poor weather, I saw no accidents. However, most of the drive from Morocco to Rensselaer was at 20 mph. We were in a line of vehicles behind a slow driver and it was very difficult to pass. The conditions really were not that bad. Anyone used to driving in bad weather could have managed at least 35 mph with no difficulty.

Here is a post from Desert Survivor about bad driving weather in Utah.