How concerned should I be about driving I70 from Vail to Denver late Saturday afternoon? I have 4wd but not snow tires. OpenSnow is projecting 5-9" of snow during the day and 1-3" at night for Vail and 2-4"/0-1" for Keystone. I would appreciate some local knowledge in deciding if I should try to alter my plans. Thanks in advance for the input.