Wildfires are creating a new forecasting challenge

When we think of summertime weather hazards, heat waves, severe storms, and flooding often come to mind. But this summer has highlighted another hazard with the potential to affect millions: wildfire smoke. 

In July, smoke from large wildfires in western Ontario spread southeastward across the Midwest and Eastern US, blanketing major population centers including Chicago, Minneapolis, Detroit, and cities along the I-95 corridor from Boston to Washington, DC. Later in July and into early August, wildfires ignited across the Pacific Northwest, threatening homes and businesses near Spokane and creating air quality concerns across the region. 

A growing threat, with growing impacts 

Wildfires are far from a new hazard. In Ontario, where the first round of fires originated, the legislated fire season runs from April 1 to October 31. During this period, measures are taken to reduce the risk of wildfire ignition and spread, but fires can still occur naturally due to dry thunderstorms, or as a result of human activity. Research also suggests that climate change is increasing the likelihood and severity of wildfire events. In Oregon, for example, more than 2 million acres have already burned this season, surpassing the state's previous record. 

Understanding wildfire risk before ignition 

For forecasters, however, the challenge extends beyond predicting where and when a fire might start. Wildfire behavior and the resulting smoke are influenced by a complex combination of atmospheric and surface conditions. Meteorologists consider factors such as relative humidity, wind speed and direction, soil moisture, and the potential for dry lightning when assessing wildfire risk. Yet even with these inputs, it is impossible to predict exactly where a fire will ignite. 

Once a fire starts, the forecasting challenge shifts. High-resolution models can help project the spread and intensity of smoke in the near term, while models such as the ECMWF provide smoke forecasts several days ahead. These forecasts can have implications well beyond air quality. During the recent smoke event in the Eastern US, for example, heavy smoke reduced incoming solar radiation and contributed to temperatures in Boston being cooler than forecast. The same reduction in solar radiation also affected solar power generation, which fell short of model projections. 

Forecasting the ripple effects of wildfire

These cascading effects highlight why wildfire intelligence is becoming increasingly important for governments and businesses. As populations grow in wildfire-prone areas and changing climate patterns contribute to greater fire risk, organizations need more than an indication that a fire is burning.  

The challenge is increasingly about connecting fire activity with the weather and air-quality conditions around it: how a fire may evolve, where smoke could travel, how air quality may change, and what those conditions could mean for communities, infrastructure and weather-dependent operations. 

For forecasters and decision-makers, this means bringing together multiple sources of information across different time scales. Observations can show what is happening now, while weather, fire and air-quality forecasts can provide insight into what may happen next. Together, they can help organizations move from reacting to wildfire impacts to anticipating them.