That ended up being the weekend of the first good snow in the Chisos back in December. We spent time in the Chisos and then biked around some other areas of the park. The write up is under trip reports and titled "A snowy, cloudy Big Bend" or something similar to that. I'm afraid it may be a little while before I get a chance to go down and try it as I already have overnight snowshoeing and backpacking trips to CO and Sedona scheduled for the next 2 months.