Originally Posted by 700LH
Closest I found easy was Dillon,
Events, 09/15/2017, fog, rain, snow.

https://www.wunderground.com/histor...qdb.zip=&reqdb.magic=&reqdb.wmo=


According to this LINK, conditions at Dillon at around 10.30 am were snow and fog, visibility about 800 m (1/2 mile). By 11.24 conditions were heavy snow, visibility down to 400 m (1/4 mile).