UPDATE: Cold front pushed through Helena shortly after noon and winds have gusted over 50 mph, sustained over 30 mph from the west. The Corral fire in the Scratchgravels has re-intensified and smoke is blowing through the Helena Valley. Air quality in the path of the smoke is UNHEALTHY, but mostly GOOD everywhere else. Strong frontal winds will likely have a similar effect on the fires in southwest Montana, and receptors downwind will stay UNHEALTHY FOR SENSITIVE GROUPS until fires die down overnight.
EARLIER TODAY: Shortly after 4:00 PM yesterday, a wildland fire in the Helena Valley, specifically in the Scratchgravel Hills, quickly intensified and spread. At the start of the fire, strong southwest winds were carrying the smoke plume across the north valley and over the Big Belt Mountains, combining with a large smoke plume from fires in southwest Montana. By sunset, the combined plume had reached across the Canadian border, passing over Great Falls and parts of the hi-line, between Shelby and Havre. As the evening progressed, the wind changed direction, coming mostly from the northwest, as the plume started to lie down in the valley.
Based on visibility guidelines, air quality in the valley as of late this morning is MODERATE. Similar air quality conditions are seen between Butte and Bozeman, where three wildfires continue to burn. Smoke from nearby states and the Central Plains has blown into eastern Montana, causing some haze and some regions of MODERATE particulate concentrations.
A cold front is making its way across the state today, bringing cooler temperatures but very strong winds as well. Winds are already gusting from the west over 20 mph in parts of western and northwestern Montana, temperatures are dropping, and rain is staying west of the Divide. Most of the precipitation is expected to stay west of the Divide and just east of the northern Rocky Mountain Front. The cold front will stretch from Helena to Bozeman to Great Falls shortly after noon. Eastern Montana will heat up again today as the cold front is not expected until this evening there. Red Flag Warnings remain in effect for southwestern and south-central Montana until 9:00 tonight, and for eastern and southeastern Montana until midnight. By Wednesday, fire concerns will diminish as temperatures fall below normal and relative humidities increase. The cold front today will also help to clear out existing smoke to improve air quality to GOOD in most locations.
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A wildfire in the Helena Valley ignited late yesterday afternoon, putting more smoke into the air around Helena, Great Falls, and parts of the hi-line. Three other wildfires continue to burn between Butte and Bozeman, and smoke plumes have taken a similar southwest-to-northeast trajectory. Air quality in these locations is GOOD to MODERATE. Parts of eastern Montana have also seen GOOD to MODERATE air due to fires in nearby states. A cold front will pass east across the state today, bringing strong winds this afternoon and cooler temperatures for Wednesday. Red Flag Warnings are in effect for southwest and south-central Montana until 9:00 tonight, and for eastern and southeastern Montana until midnight. By Wednesday, cooler temperatures and higher humidity will ease fire danger. |