( CNN ) -- If you look at the images of destruction from Colorado , it 's not hard to see why officials have called the Waldo Canyon Fire the most destructive in state history . Last week , it was like a monster roaring down a mountainside , swallowing houses whole . And that 's not even the biggest blaze at the moment . A fire in Montana 's Custer National Forest is raging over 186,800 acres . As many as 13 new large fires were reported Sunday , the National Interagency Fire Center said . In all , 14 states , mostly in the West , are dealing with active fires . Does it seem like wildfires in the United States are getting bigger and badder ? It 's a question fire expert Max Moritz has been hearing a lot lately . That 's because the University of California , Berkeley professor published a report on global fire risks on June 12 , just before the massive fires in Colorado ignited . `` In the long run , we found what most fear -- increasing fire activity across large parts of the planet , '' he said . Moritz 's study concluded that some areas of the world , including the western United States , `` should brace themselves for more fire . '' 4 die fighting Western fire . Nationally , wildfires have scorched about 2.2 million acres this year . That 's less than half the number in July of last year . But the gap has been closing rapidly over the last few days , said Ken Frederick , spokesman for the National Interagency Fire Center . He said the United States was on pace to match or go beyond last year 's acreage . In some parts of the country , like Colorado , this year is far worse . `` Certainly for a number of people in communities , 2012 is a terrible year , '' Frederick said . `` I do n't want to take anything away from that . '' Weather conditions played a big role , Frederick said . Snowfall was below average in many Western states and dry conditions helped fuel this year 's fires . `` The winter of 2011-2012 really dealt the cards , '' Frederick said . The frequency and length of the fire season for forest fires has increased substantially due to higher temperatures and earlier spring snowmelt , found a 2009 report by the U.S . Global Change Research Program . `` These changes in climate have reduced the availability of moisture , drying out the vegetation that provides the fuel for fires , '' the report said . Climate changes have also contributed to major insect outbreaks , the report said , . About 1.5 million acres in Colorado have been infested by pine beetles , which kill trees and make them fodder for fire . `` I imagine that this is just the opening salvos of what we 're going to see this summer , especially if the temperatures stay up , '' said Michael Archer , who writes a newsletter of wildfire news . Moritz listed several factors in what makes wildfires wilder . How fast is the fuel for the fire growing ? How flammable can that fuel get ? What is going to ignite the fire ? While weather is a key contributor , there 's debate over whether Western states are victims of climate change . Moritz said the record temperatures and lack of humidity are characteristics of climate change -- hallmarks of what weather models predict we should expect under climate change . Record heat , storms bring despair , 'horror ' `` But to say it is climate change ? I think most of us are cautious about saying that , '' he said . Some experts blame bad forest management . Others like Archer say firefighting resources are inadequate . Still others say people are affected due to building in fire-prone areas . Moritz says it 's probably all of the above . The problem is just complex enough , he said , to lead to misinterpretations . He said the conversation should focus instead on how people can better coexist with fire as they do with other hazards . Americans build in extra precautions for houses in flood plains or on earthquake faults ; why not do the same for houses in fire-prone areas , Moritz said . `` This is a really big wake-up call , a very big warning in all the losses we are seeing , '' Moritz said of this year 's fires . That warning was particularly stern Tuesday as millions of Americans prepared for the Fourth of July . For many in Western states , the fires will force different sorts of celebrations . `` Everybody is kind of worried , '' Archer said . `` They 've seen 32,000 people evacuated . You 're going to see a lot of nervous people in the West . '' No grilling or sparklers . And no fireworks bursting in air . As temperatures sizzle , fireworks are even more risky . Triple-digit strategies for staying healthy . More than 1.2 million customers lack power amid unrelenting heat .
A recent study finds increasing fire activities across the planet . Fire-plagued Western states should brace for more in the future , the study says . Weather is a big factor , though a combination of factors can also be cited . Building in fire-prone areas should be an exercise in caution , one expert says .