Right! The "SN" in METAR means moderate snowfall. My opinion, it was heavy snowfall (my home place is about 9 nm from ALA airport). I made some photos through window about midnight (it was 3 hours before crash). It was terrible weather conditions near my place.
The RW was covered with dry snow with depth up to 10 mm and braking action was .32 (METAR) The snow looked dry but my sat dish (the tilt about 70) is covered with snow now (it is in 2 days after snow fall).
Normally taxi to RW05 takes 5 min (not more), but if another a/c has landed and is back tracking, it can take up to 20 -25 min.