It's not the amount of snow that's a concern tonight, but light snow being compacted and becoming extremely icy in the Butte and Homestake Pass area.

According to the National Weather Service:

WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 10 PM MST THIS EVENING...

IMPACTS/TIMING: LIGHT POWDERY SNOW FALLING OVER ALREADY SLICK SURFACES WILL BRING A SLICK COMMUTE WITH BLACK ICE THIS AFTERNOON AND EVENING.

TODAY AND THIS EVENING: SNOW SHOWERS ARE EXPECTED TO DEVELOP AND PICK UP IN INTENSITY THIS AFTERNOON.

THERE IS A GOOD POTENTIAL FOR A FEW STRONG SNOW BANDS WHICH WILL BRING TRAVEL DIFFICULTIES. SPECIFICALLY SUDDEN REDUCTION OF VISIBILITY TO JUST A FEW HUNDRED FEET.

USE YOUR HEADLIGHTS AND BE ALERT FOR SUDDEN CHANGES.

THIS EVENINGS COMMUTE MAY ALSO BE DIFFICULT AS MELTING WET ROADS WILL REFREEZE. FRESH LIGHT SNOW ON ICE WILL MAKE TRAVEL DIFFICULT.

LOCATIONS IMPACTED INCLUDE... BUTTE... GEORGETOWN LAKE... HIGHWAY 12 GARRISON TO ELLISTON... HOMESTAKE PASS... MACDONALD PASS