In May, record-breaking temperatures tipped over 90 degrees Fahrenheit (exceeding normal temperatures at this time of year by nearly 40 degrees) before an extreme wildfire erupted at bone-dry Fort McMurray, a Canadian city central to Western Alberta’s tar sands oil region. The inferno has engulfed more than 1,600 buildings, including one out of every five homes, and has pushed nearly 100,000 people to flee the city, the largest evacuation in Alberta’s history. Left behind are the near unrecognizable remnants of residential streets, burned churches and countless cars.
The Alberta blaze may just be the beginning of what is shaping up to be a tough fire season in parts of the West. The wildfire season is changing; blazes are hotter and larger than they used to be and seasons are beginning earlier and lasting longer. The Fort McMurray fire “is consistent with what we expect from human-caused climate change affecting our fire regime,” Mike Flannigan, wildfire researcher at the University of Alberta, told Climate Central as the fires were burning last week.
This winter, a Super El Niño has complicated the outlook for fire season. While it was expected to bring big storms for parts of the West, climatologists say the weather pattern underperformed in states like New Mexico, Southern California and Arizona, which were expected to see more precipitation from the weather phenomenon.
In turn, the pattern could exacerbate the wildfire season, leaving already arid states even drier and bolstering grassy fuels in states that did manage to get precipitation, says Wally Covington, climatologist and fire expert from Northern Arizona University. “We’ve got this rotating El Niño-La Niña cycle, but we also have global warming going on, so we’ve been getting some unusual events associated with weather patterns,” Covington says.
El Niño, a weather pattern created by warming waters in the Pacific Ocean, typically brings more winter precipitation to the southern half of the West and less to the northern. That means more mild winters in Northern California, the Pacific Northwest and across the Northern Rockies. La Niña, on the other hand, begins once the Pacific waters cool. When that happens, the Southwest grows drier, while the northern half of the region gets more rainfall.
This cycle, El Niño left much of the Southwest — New Mexico, Arizona, South and Central California and much of Nevada and Utah — parched, exacerbating drought conditions. Yet in Southern California, El Niño brought just enough moisture for grassy fuel loads flourish, according to the National Interagency Fire Center (NIFC), in Boise, Idaho. In each case, El Niño has laid the groundwork for a nasty fire season. None of these states will likely catch a break as La Niña moves in, making the Southwest hotter and drier than normal this year.
In California, which is now in its fifth year of drought, a paltry snowpack, dry soils and warmer temperatures make it easier for fires to spark. When they do, wildfires — caused by either humans or lightning strikes — can spread faster and burn longer. El Niño was expected to bring above normal snow and rainfall to Southern and Central California, but the weather pattern fell short. On the whole, California snowpack is just below normal.
According to the fire potential outlook report by NFIC published in May, wildfire danger for July and August this year will be above normal for most of California. “The effect of the drought on vegetation across the state has been severe,” says Ed Delgado, information specialist for NIFC. In Central California’s Sierra foothills, desiccated timber is cause for even more worry. “Over 50 percent of the old growth long-needle pines are dying or are dead,” Delgado says.
Large trees that have been drying out for several years are combined this year with taller quick-growth grasses, thanks to El Niño precipitation. Together, they add up to a lot of fuel. In California, El Niño has been “both a blessing and a curse,” says Daniel Berlant, spokesman for Cal Fire. Taller grasses and precipitation has lead to earlier preparations for the wildfire season. “Oddly, we’re taking advantage of El Niño,” Bertland says. “The extra rain earlier in the year added to our fuel loads, but it has also allowed us to do prescribed burns earlier.”
Since Jan. 1, the state has already had more than 700 fires (compared to more than 1,000 at the same time last year), and in February, California hired an additional 400 firefighters to do earlier fire prevention work. Those preparations, Bertland says, will hopefully curb more extreme fires. “While fire danger is up this year from last, we are going into the season far more prepared.”
Early in the season, May through June, New Mexico, Arizona and parts of southern Nevada generally have the highest wildfire potential in the West. But this year, El Niño precipitation bypassed New Mexico and Arizona almost completely, leaving the two states with the lowest snowpack and precipitation levels in the region. And by July and August, a “typical” La Niña wouldn’t be expected to bring more precipitation to those states, Covington says. “El Niño did precisely the opposite of what we expected for New Mexico and Arizona. The game is changing for predicting wildfire outlook. We really don’t know how things will shake out.”
NIFC projections show an earlier than normal peak for wildfire danger in New Mexico and Arizona in May and June and then subsiding and shifting the highest wildfire potential to California and much of northern Nevada through August.
Colorado, with an above average snowpack this year, is in a relatively good position. With consistent precipitation forecasted through much of May, the fire season in the state will be slower to start, says Klaus Wolter, climate researcher for the Cooperative Institute for Research in Environmental Sciences, at the University of Colorado. For the May through August wildfire season, Colorado wildfire potential will be normal, according to NIFC.
Other higher elevations areas like the Rocky Mountains in Montana and Wyoming, as well as the northern Sierra Mountains in California, have bolstered snowpack from El Niño, decreasing the risk of dangerous wildfires early in the season.
