“So while the spring outlook for this year from NOAA looks quite similar to last year, there is a key difference about this spring, which is that the drought has expanded eastward, pushing 70% of Texas — which was less impacted over the last two years — into severe drought,” Justin Mankin, assistant professor of geography at Dartmouth College and co-lead of NOAA’s Drought Task Force, told CNN.
In Colorado, around 19,000 residents were allowed to return to their homes Tuesday after a wildfire broke out near the Boulder area. The fire ignited on Saturday afternoon and burned out of control Saturday evening, which prompted the evacuation orders.
Daniel Swain, a climate scientist at the University of California at Los Angeles, said the transition period between winter and spring is usually when the Plains states tend to experience their wildfire season. But there have been some unusual trends in recent fire activity there, Swain told CNN.
“Even if there is still a relative lull in the winter, it’s not as deep a lull as used to be,” Swain said, noting that scientists are “seeing periods in the winter which used to have virtually zero fire risk, in some places now having appreciable fire risk, in some cases.”
Climate researchers have said two major factors have contributed to the West’s multiyear drought: the lack of precipitation and an increase in evaporative demand, also known as the “thirst of the atmosphere.” Warmer temperatures increase the amount of water the atmosphere can absorb, which then dries out the landscape.
That’s also true for places like Colorado and interior Texas, away from the Gulf Coast, Swain said. When the atmosphere extracts moisture from the soil without returning that water in the form of precipitation, there’s going to be less water available to those plants.
“And that’s the main climate change connection — the effect that the warming and drying is having on the vegetation aridity itself,” Swain said. “In most cases, the drier vegetation becomes, the more flammable it becomes. In some cases, it’s an exponential relationship where each additional increment of drying makes it increasingly more flammable at an increasing rate.”
“That’s why even a few degrees of warming can make a big difference,” he added.
“The commonality that we’re seeing across most fire-prone regions on Earth is an increase in the number of extreme fire weather days, and also an increase in the magnitude of the very worst severe fire weather days,” Swain said. “And that is linked to human-caused climate change.”
