In situations like that, I stay home. So does everyone else at my workplace, because my company isn't run by a bunch of pigs who insist on workers commuting in dangerous conditions. We also have a setup where everyone can telecommute at need and does telecommute frequently, so it's not a big deal, but we have a standing rule of "If you think it's too dangerous to come in to work, stay at home." Frankly, it's a no-brainer to me, and I don't understand why any company would expect otherwise.