al adams

Was recently on a wet dirt (forest service) road that was flat but wet; my new 2008 RX400h fishtailed almost uncontrollably at 10-15 mph. Had the computers checked the next week and all read "good to go." Wondering/worrying about how it will handle in the Sierra snow in a couple of days. It's all-wheel drive and is supposed to be good in the snow, yes? Any experience/advice to illuminate this apparent conundrum?