Thank God you are ok. I have been to Austin several times and out to Lake Travis, and it is very tough terrain in the daylight much less during rain or fog.
Side note-my grandparents used to live in Jollyville. My uncle graduated from Round Rock High School way back in like 1974. I grew up visiting her in the summer time and grew to love that place. Of course where she lived is now grown up with a subdivision, but I remember quiet summer evenings when she let me sleep out on the porch and the occasional car sound I heard, but mostly just peaceful and quiet and beautiful. Anyway, pardon my trip down memory lane. I am glad you are ok. Hope it didn't shake you up too bad.