HELENA, Montana — Montana's fire season began quietly but has quickly grown to the second-largest so far this decade after lightning storms last month ignited a rash of blazes that spread rapidly amid bone-dry conditions.
This season is not over yet, with at least 35 large and small fires still burning in Montana, though a cold front moving through the region is expected to bring a half-inch of rain or more to some parts of western and central Montana by Thursday.
"I can't say with any confidence that it's a season-ending event, but I think it's a season-slowing event," said Megan Vendenheuvel of the National Weather Service in Great Falls.
A typical season-ending storm brings more than an inch of rain over a wide area and several inches of snow in the mountains, she said.
More than 522 square miles have burned this year across Montana, about two-thirds of that in the state's national forests, according to data from the Northern Rockies Coordination Center. Most of those fires were lightning-caused and ignited in the western half of the state, which has been in severe drought since early this summer.
The drought combined with other factors — fuel buildups, climate change, species invasions, disease infestations — created a lot of potential for fire, U.S. Forest Service spokeswoman Elizabeth Slown said.
"Then we also had lightning storms that moved from California up into Oregon, Washington, Northern Idaho and Montana, igniting numerous wildfires within a couple of days," she said.
That outbreak, along with large fires burning in Washington state and California, created a resource shortage in the state and for a period made the region that includes Montana and Northern Idaho second on the national wildfire priority list.
It's also been an active fire season for the National Park Service, with two major fires burning in Glacier National Park. Those fires are now smoldering after rain and snow fell in the region earlier this month, while fresh rain slowed a 4-square-mile lightning-caused wildfire burning in Yellowstone National Park.
Montana Department of Natural Resources and Conservation fire information officer Crystal Beckman estimated the state has responded to fires burning on 65 square miles so far this season. About $10.6 million of a $90 million firefighting reserve has been spent so far, she said.
Montana's biggest fire season since 2010 was in 2012, when 1,900 square miles burned on federal, state, reservation and private land. That year, most of the fires were burning in the southern and eastern parts of the state.
Those fires burned dozens of homes in Musselshell, Rosebud and Powder River counties, including the Northern Cheyenne Indian Reservation.