Tracking the changing forest fire season 

Fort McMurray fire one example of Hotter, dryer patterns noted after super el Niño

click to enlarge SHUTTERSTOCK PHOTO - into the fire At its peak, the massive forest fire near Fort McMurray engulfed more than 485,600 hectares in Alberta and forced the evacuation of more than 80,000 people.
  • shutterstock photo
  • into the fire At its peak, the massive forest fire near Fort McMurray engulfed more than 485,600 hectares in Alberta and forced the evacuation of more than 80,000 people.

The devastating blaze near Fort McMurray in May engulfed more than 485,600 hectares (1.2 million acres) of boreal forest and, at the height of the fire, more than 80,000 people were evacuated and almost 4,000 employees of Alberta's tar-sands oil region were unable to work.

The wildfire season is changing. Blazes are much hotter and larger than they used to be, and seasons are beginning earlier and lasting longer. The characteristics of the Fort McMurray fire fit the trend of the mega-fires as the climate warms, said Yong Liu, researcher and head of the Atmospheric Science Team of the U.S. Forest Service.

This winter's Super El Niño has complicated the outlook. While the Pacific Ocean's warming waters were expected to bring big storms to the southern half of the West, climatologists say the results disappointed much of the area. That left New Mexico, Arizona, central California and much of Nevada and Utah parched, exacerbating drought conditions, according to the National Interagency Fire Center (NIFC), in Boise, Idaho.

In states bypassed by the strong El Niño, the groundwork has been laid for an intense fire season, said Wally Covington, climatologist and fire expert from Northern Arizona University. Meager snowpack, dry soils and warmer temperatures will make it easier for blazes to spark and spread. According to NIFC's May outlook, California's near-normal snowpack (the best since 2011) has since depleted rapidly, and the wildfire season is expected to be worse than usual this year, thanks to high fuel loads. Statewide, the ongoing drought has left huge stocks of desiccated timber, while in the state's southern region, just enough El Niño precipitation fell to encourage prolific grass growth.

That's "both a blessing and a curse," said Daniel Berlant, spokesman for Cal Fire. The El Niño-encouraged fuel loading has forced his agency to prepare for an earlier fire season, but "the extra rain earlier in the year has also allowed us to do prescribed burns earlier."

Elsewhere in the West, NIFC projections showed an earlier-than-normal peak for wildfire danger in New Mexico and Arizona for spring, but now above-average temperatures and rapidly drying fuels will bring a higher fire risk to California, Nevada and southern Idaho. The Rocky Mountain region — Colorado, Wyoming and Montana — is in relatively good shape because of deep snowpack and increased precipitation through May. "Super El Niños" like this one, followed by longer periods of warm La Niña conditions, are just one symptom of the larger climate shifts that many climatologists expect the arid West to see. El Niño is now transitioning to La Niña as the Pacific cools. Typically, those patterns balance each other out. But since this year's El Niño bypassed areas expected to receive more precipitation, La Niña — which usually brings less precipitation to the region — is likely to cause the dry Southwest to become even drier.

"Once La Niña is firmly in place, we would expect to see more fires in the southern half of the Western U.S. through the fall," Covington said. "The Southwest is not in a good position."

Paige Blankenbuehler is a High Country News editorial fellow.



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