A wetter-than-average winter and spring are helping to ease drought conditions across the Great Basin. However, an active fire season may now be on the horizon, according to meteorologist Gina McGuire of the Great Basin Geographic Area Coordination Center. McGuire, who spoke at the Desert Research Institute in Reno in early April as part of the Great Basin Climate Forum, studies fire weather—specifically, the effects of drought and recent precipitation on the upcoming wildfire season.
The relationship between precipitation and wildfires is somewhat complicated, says McGuire. In the Great Basin, wet conditions during winter and early spring can lead to increases in the growth of fine fuels such as shrubs, native grasses, and an invasive grass called cheatgrass, which can increase fire risk later in the season.
“In the Great Basin, when we get a lot of rain, things green up,” McGuire said. “April showers bring May flowers. It also brings a lot of cheatgrass. It brings a lot of grass to the Great Basin, which is a lot of fuel to burn.”
For the past few years, drought conditions may have actually helped to decrease wildfire activity in our region. Although drought causes heavy fuels such as dead trees to dry out and become more flammable, droughts also tend to reduce the growth of shrubs and grasses that spread wildfires.
“We’ve had below-average fire seasons with respect to the fire size, the amount of acreage we’ve burned across the Great Basin,” said McGuire. “We still continue to have fires, but they just haven’t been becoming as large across the state area.”
The timing of precipitation matters, said McGuire. Rain that comes later in the season can keep fuels moist, helping prevent the spread of wildfires.
“Precipitation is not only important with how much we get, but it’s important when that occurs,” McGuire said. “If it occurs in the spring, we’re going to get a lot of growth. If it occurs in July and August, we’re not going to get a lot of wildfires because it’s going to be too wet.”
In 2015, for example, a very wet July on top of the ongoing drought helped to keep the Great Basin’s summer wildfire season to a minimum. According to data from the Great Basin Geographic Area Coordination Center, wildfires on average burn approximately 1.1 million acres of the Great Basin each year. In 2015, just over 500,000 acres burned. Nevada had an especially light fire season, in which only 42,279 acres burned—down from 59,377 acres in 2014, and 162,841 acres in 2013.
So, what might we expect to see in 2016? “It looks like we’re going to have a really wet April,” McGuire said. “That’s probably going to promote a little bit more grass growth. Right now the focus for an above-normal fire season would be Southern Nevada for June, the western and northern parts of Nevada for July and August, and the higher elevations of the Sierra Nevada as we move into August.”