TORONTO -- NASA estimates smoke from the Australian wildfires will circle the globe and then once again hover above the country.

In a blog post, the agency said smoke from the fires “is expected to make at least one full circuit around the globe, returning once again to the skies over Australia.”

The agency did not give an estimated date for when the smoke is expected to return, but did say that as of Jan. 8, the smoke was crossing South America. The smoke is also expected to remain in the Southern Hemisphere, meaning it will never hit Canada.

The fires have already had “a dramatic impact on New Zealand,” NASA said. New Zealanders are facing severe air quality issues, and mountaintop snow is being darkened.

The wildfires have also formed dozens of Pyrocumulonimbus storms, which are essentially thunderstorms fueled by the heat from the fires and the water in the atmosphere. NASA said these storms “provide a pathway for smoke to reach the stratosphere more than (16 kilometres) in altitude. Once in the stratosphere, the smoke can travel thousands of miles from its source, affecting atmospheric conditions globally.”

The agency is currently studying the global effects of these storms, including their impact on temperatures.

Firefighters have been battling the devastating fires for more than three weeks, but on Sunday officials said changing weather conditions have allowed them to tackle the fire more effectively.

The fires have claimed the lives of at least 27 people, destroyed more than 2,000 homes and burned an area larger than the state of Indiana.

With files from The Associated Press