US wildfires spanning across the West are getting bigger and more frequent, in part due to climate change, over the last 30 years. A new study, published in the American Geophysical Union (AGU), says as much.

Scientists, led by that geographer Philip Dennison, blame drought caused by rising temperatures for the upward trend. They used satellite data to measure areas of more than 1,000 acres burned by large fires from Nebraska to California since 1984. These fires increasingly consumed areas at a rate of nearly 90,000 acres a year - an area the size of Las Vegas.

The hardest-hit regions were the Rocky Mountains, Sierra Nevada and Arizona- New Mexico mountains, as well as areas ranging from California to Texas.

"We looked at the probability that increases of this magnitude could be random, and in each case it was less than 1 percent," Dennison, of the University of Utah in Salt Lake City, said in a news release.

The researchers' claim does not seem to be so far off base. They found that most areas severely affected by drought also experienced more fiery conditions.

"Most of these trends show strong correlations with drought-related conditions which, to a large degree, agree with what we expect from climate change projections," co-author Max Moritz, a fire specialist, said.

But they don't go as far as to directly linking the number and size of these fiery blazes to human-caused climate change. Other factors may be exacerbating these wildfires, the study speculates.

Past forest management practices that suppressed fires and allowed fuel supplies to build up may also be responsible, said US Geological Survey ecologist Jeremy Littell.

"It could be that our past fire suppression has caught up with us," said Littell, who was not involved in the study. "It could also be a response to changes in climate, or both."