Alaska is on track to have one of its worst wildfire seasons on record, propelled by a combination of warming average temperatures, a historically mild, relatively snowless winter and extremely mild spring.

So far this year, 1.88 million acres have gone up in smoke, from 617 individual fires. June 2015 beat June of 2004 in terms of both number of fires and amount of acres burned, which means this year is now outpacing the state's worst wildfire season ever recorded.

With hundreds of fires still burning in Alaska and in Canada, smoke has made it all the way across the Midwest and Mid-South to the Atlantic Coast, crossing over the Atlantic Ocean off the coast of South Carolina on Wednesday.

Smoke from wildfires burning in Alaska and Canada reached the Atlantic Ocean on July 1, 2015. Image: NASA

In fact, the smoke has been so thick in some parts of the lower 48 states that daytime high temperatures were lowered by a few degrees compared to what they would have been in its absence.

So many fires are burning simultaneously in Alaska that the U.S. Air Force has joined the fight, using Lockheed C-5M Galaxy aircraft from California to ship firefighting supplies to Alaska. Typically, these supplies are trucked up the Alaska highway from Canada, but the urgency of the fire situation meant there was a need for a faster delivery, according to the Alaska Division of Forestry.

Cumulative acres burned to date in Alaska in 2015 and 2004. Image: Alaska Forest Service/Facebook

In 2004, a total of 6.6 million acres burned across Alaska, which was more than eight times the 10-year acreage average. There were five days in 2004 when the single day total of burned area beat the annual acreage burned in three separate years, including 2001, according to the state's division of air quality.

The U.S. Air Force joined the massive firefighting effort currently underway in Alaska on Sunday by helping to expedite... Posted by Alaska DNR- Division of Forestry (DOF) on Monday, June 29, 2015

Fortunately, rain showers have returned to portions of Alaska for the time being, leading state authorities to drop outdoor burn bans that had curtailed camping activities in time for the Fourth of July holiday. However, the fires currently burning are not likely to be fully extinguished anytime soon, and additional lightning strikes may spark new blazes. Computer model projections show another area of high pressure may bring unusually mild and dry conditions to the state by early next week.

Burn ban is lifted for many areas. Be safe and firewise this weekend as warmer & drier weather will be building in. http://t.co/EgYT4ySNGi — NWS Alaska Region (@NWSAlaska) June 30, 2015

One of the worrying trends about fires in Alaska, as well as in Canada and Siberia, is the tendency for more fires to take place north of the Arctic Circle, in ecosystems with frozen soil that has locked carbon away for thousands of years or longer. When it is burned, that carbon is released into the atmosphere, leading to a positive global warming feedback.

Alaska has warmed more than twice as fast as the rest of the country in the past 60 years, with about 3 degrees Fahrenheit of average warming overall, according to a report released last week from the nonprofit research group Climate Central.













Team Rubicon firefighters fighting the Aggie Creek Fire in Alaska in June 2015.





Image: Photo by Samantha Storms/Bureau of Land Management









The analysis found that the number of large wildfires, each burning 1,000 acres or more, increased in the 1990s. The past decade saw about twice as many large wildfires as were recorded during the 1950s and 1960s. The area burned by wildfires in Alaska is also skyrocketing as temperatures warm, snow cover melts earlier in the year and weather patterns change.

Perhaps more importantly, researchers found that Alaska’s wildfire season is about 40% longer than it was in the 1950s. The fire season is now about three months long, from May to August, which is more than a month longer than it used to be. In addition, fires are encroaching on areas that have been immune from them during colder times.