US: Wildfires threat present for the western and central regions through November

Wildfires are likely to cause sporadic, localized disruptions to transport and business operations across the western and central US through at least November. Wildfires are a typical feature of the summer and fall across the western and central US, particularly after long dry spells or during extremely high temperatures. Emergency services are typically swift to respond and are able to contain a majority of fires quickly. However, occasionally severe fires can get out of control and threaten homes and businesses; authorities may order the evacuation of communities in the vicinity at short notice.

Forecast models indicate the wildfire potential is likely to be below average across much of California June-July, near-normal August, and above-average September. Above-average fire potential is also forecast in parts of the Great Basin June-September, the Desert Southwest June-August, the Northwest July-September, and the central plains July-August. Near-normal wildfire potential is forecast across the rest of the affected area June-September.

Wildfires can lead to evacuations, road closures, and ground transport diversions. Disruptions to arterial roads are possible. The scarcity of alternative routes in some areas means that significant transport disruptions are possible at times. While authorities are experienced in minimizing the potential impact, roads in remote regions are likely to be disrupted for more extended periods due to their relative inaccessibility. Authorities could close routes in the wildfire complex and evacuate communities due to fire activity and the needs of response operations. Traffic flows could also be disrupted during re-entry periods after authorities lift evacuation orders.

Low visibility from smoke and possible ashfall could contribute to traffic delays, congestion, and prompt short-notice flight disruptions if wildfires occur near airports.

Railways can also experience occasional cancellation of services and long delays. Power outages are possible in places due to damaged infrastructure or intentional power cuts to prevent infrastructure damage or to help prevent the spread of the fires.

Smoke from wildfires can spread large distances due to prevailing wind conditions and impact areas far from the wildfire. Wildfire smoke is a mixture of gases and fine particles from burning trees, plants, and possibly building materials. Such smoke can hurt the eyes, irritate the respiratory system, and worsen chronic heart and lung diseases. Smoke may also worsen symptoms for people who have pre-existing respiratory conditions, such as respiratory allergies, asthma, and chronic obstructive pulmonary disease (COPD).