An AIR QUALITY ALERT has been issued for Lincoln County until 9AM MDT August 4, 2015 due to elevated particulate concentrations. Air quality in Libby is currently UNHEALTHY. State and Local health officials recommend that people with respiratory or heart disease, the elderly, and children should avoid prolonged exertion; everyone else should limit prolonged exertion. Another update will be posted at 9AM MDT on August 4, 2015.
Air quality impacts continue across western Montana today as fires in Washington, Oregon, and Northern California continue to send smoke into the state. The most significant impacts continue to be in Northwest Montana, where 24-hour average air quality remains UNHEALTHY in Libby. Elsewhere, 24-hour average air quality is UNHEALTHY FOR SENSITIVE GROUPS in Flathead Valley, Missoula, Seeley Lake, and Frenchtown, and MODERATE in Helena, Butte and Broadus. The monitor in Hamilton was down until earlier this morning but measurements taken since then indicate average air quality in the Bitterroot is likely UNHEALTHY FOR SENSITIVE GROUPS. In Eastern Montana, skies are hazy but so far air quality remains good as the smoke has stayed aloft in most places.
The main contributor to this smoke is likely the Wolverine Fire in Washington State. This fire has been displaying extreme fire behavior has been producing a large amount of smoke on satellite for the past few days. The fire is under a red flag warning today so additional smoke impacts are likely. Smoke is also visible across much of Oregon, Idaho, and Northern California today from large, active fires burning across the west. This smoke is likely also contributing to the widespread smoke under the ridge of high pressure that has impacted our area for about a week. Here in Montana, the Reynolds Creek fire is nearing in on 4,000 acres and 67% containment. Smoke impacts in Glacier are mainly due to transported smoke from Washington.
Change is on the way tonight in the form of a cold front pushing through the state. This cold front is expected to swing through starting this evening and will bring breezy conditions to areas along the Idaho/Montana border first, and move eastward across the state. Prior to the cold front arriving, smoke impacts may worsen in some areas after nightfall as smoke may settle into the valleys. The breezy conditions will hopefully bring improvement to the smoke impacts. However, strong winds over the fires may increase smoke production and carry more smoke into the state. After the cold front moves through, a low pressure trough will make its way eastward across southern Canada through Friday. This may briefly redirect smoke from the Wolverine fire away from northwest Montana but usher in additional smoke from Idaho, Oregon, and California, especially into southwest Montana. Throughout this period there is a chance of afternoon thunderstorms.
Overall, expect air quality ranging from MODERATE to VERY UNHEALTHY to impact the area for the rest of today. We may see brief improvement overnight as a cold front moves through, but the possibility exists for the increased winds to carry additional smoke in to the state. The air quality alert for Lincoln County will remain in place overnight, as hourly concentrations have been trending upwards this afternoon. We will likely see intermittent smoke impacts throughout western Montana for the remainder of the week as smoke carried from active fires continues to move into the state.
AIR QUALITY ALERT issued for Lincoln County today due to measured concentrations reaching UNHEALTHY levels in Libby, MT. Numerous fires burning in Washington, Idaho, Oregon, and Northern California are causing widespread hazy skies and smoke impacts across Montana today. The biggest driver of this smoke is the Wolverine fire in Washington. We may see some improvement overnight tonight as a cold front moves through the area, although this may usher in additional smoke due to increasing winds. A system moving through southern Canada this week may cause intermittent improvement, but smoke impacts are likely throughout the week due to the large number of fires burning to the west and southwest of the state. Smoke impacts from fires within Montana are also likely throughout this period as breezy conditions continue to cause active fire behavior.