Thanks to everyone for your suggestions.
#12: Right. I considered: "icy conditions," "black ice," etc., but I discarded them for exactly the reason you mention. "Snow, ice, and icy conditions" repeats the "ice," which is less than ideal.
Other terms, like "slippery patches" again are less than ideal, because they don't retain the punch of simple words like Schnee, Eis, and Glätte. "Slippery patches" does not work after "snow" and "ice."
I couldn't find a word which captures the meaning, but also retains the rhythm and punch of the original.
But just to be clear, I'm doing this just for fun, to send the cartoon to a friend. I don't really need perfection.