Moderate Expected Likely Dense Fog Advisory Dense Fog Advisory issued October 12 at 12:25PM MDT until October 13 at 12:00PM MDT by NWS Great Falls MT Oct 12, 9:00 PM → Oct 13, 12:00 PM WHAT: Visibility as low as one quarter of a mile in dense fog. WHERE: Portions of central, north central, and southwest Montana. WHEN: From 9 PM this evening to noon MDT Tuesday. IMPACTS: Low visibility could make driving conditions hazardous. ADDITIONAL DETAILS: Below freezing temperatures may lead to aglaze of ice on surfaces, most notably on bridges and overpasses. + Read More If driving, slow down, use your headlights, and leave plenty of distance ahead of you. Updated: Oct 12, 5:49 PM Source: NWS Alert