Alaska experiences unprecedented wildfires

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Alaska is burning this year in ways rarely or never seen, from the largest wildfire in a usually mostly fireproof region of the Southwest to a pair of fires that have ravaged forests and produced smoke that has blown for hundreds of miles to the Bering Sea community of Nome, where the normally crystalline air has been pushed into the extremely unhealthy category.

Already more than an area the size of Connecticut has burned and the usual worst of fire season awaits. Although few belongings burned, some residents were forced to evacuate and one person was killed – a helicopter pilot died last month when he crashed while trying to carry a load of equipment for firefighters.

Recent rains have helped, but longer term forecasts show a similar trend to 2004, when July rains gave way to high pressure systems, hot days, low humidity and lightning that fueled the worst fire year in Alaska.

In 2004, the area burned in mid-July was about the same as today, but by the end of the fire season, 10,156 square miles (26,304 square kilometers) had been charred.

“The frequency of these major seasons has doubled from what it was in the second half of the 20th century,” said Rick Thoman, climate scientist with the Alaska Center for Climate Assessment and Policy at the International Center. University of Alaska Arctic Research. “And there’s no reason to think that’s not going to continue.” .

Heat waves and droughts, which are exacerbated by global warming, are making wildfires more frequent, destructive and harder to fight in many places. This month, wildfires have ravaged Portugal, Spain, France, England and Germany, which have experienced record temperatures.

California has recorded its largest, most destructive and deadliest wildfires in the past five years and, with the state in the throes of drought, authorities are bracing for what could be a late summer. and an autumn filled with smoke and flames.

Alaska, the country’s largest state, was also dry. Parts of it saw an early snowmelt, then a largely rainless June that dried out the loam layer – the band of rotting moss and grass that covers boreal forest and tundra soils. This organic matter can be up to 2 feet (0.61 meters) thick, but in various stages of decomposition.

On May 31, a lightning strike on the humus layer of the Yukon-Kuskokwim Delta sparked the East Fork Fire, a region of southwest Alaska that rarely burns. Two communities with a combined population of around 700 people were threatened, but no mandatory evacuations were ordered in what became the largest wildfire on record in the delta at 259 square miles (671 square kilometers). Firefighters were able to protect communities.

A fire like that was directly attributable to climate change, Thoman said. There is more vegetation growing in the tundra, the willows and alders are thicker in the transition zone between the tundra and the forests, and the spruce trees along the river valleys become thicker and move away from these valleys .

“There has been a significant increase in the amount of fuel available, and this is due to decades of warmer springs and summers in the region, a direct result of global warming,” he said. “And, of course, fires with more fuel available burn hotter. They burn longer. They are more resilient to weather changes.

In Alaska, just over half of all wildfires are started by lightning and the rest are caused by humans accidentally, intentionally or through negligence. Of the 4,687 square miles (12,140 square kilometers) burned so far this year, only 2 square miles (5 square kilometers) have been caused by human-caused fires.

It is neither feasible nor necessary to try to fight every wildfire in Alaska. Fire plays a key role in the state’s ecology by clearing low-lying debris, thinning trees, and renewing plant and animal habitats, so Alaska generally leaves most to die out or wait let the rain and snow do the work. Firefighting resources are used to fight fires in populated areas.

So far this year, there have been about 145,000 lightning strikes in Alaska and adjacent parts of Canada, according to the Bureau of Land Management’s Lightning Detection Network. A staggering 42% occurred between July 5 and July 11 when weather systems produced rain, but around 50 fires were also started.

“Having concentrated lightning, where we get a significant fraction of the entire season’s lightning in a row in a few days, is actually pretty typical for Alaskan lightning,” Thoman said. “Lots of lightning in this concentrated area which started quite a few fires in areas that hadn’t had fires until now.”

Although there was little loss of property, smoke from the fires caused dangerous breathing conditions. In one case, two fires burning near Lake Iliamna joined and burned about 75 square miles (194 square kilometers) of boreal forest in one day, creating smoke and ash that high winds carried hundreds of miles away. kilometers northwest to Nome, pushing the air quality index into the extremely unhealthy category.

“I never thought you could pick up such poor air quality 400 miles from active fires, and that’s a testament to how hot these fires are,” Thoman said.

Mark Thiessen, Associated Press

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