Rapid plant growth from wet weather heightens wildfire risks later in season, officials say
Consistent rain storms over Summit County have dampened wildfire fuels countywide, but they have also led to the growth of grasses and underbrush, Summit Fire & EMS’s Wildland Division said. Once dry, those quick-burning fuels can ferry fires between larger fuels like timber — and from tree lines to homes — when lawns aren’t maintained, officials warned.
Summit Fire & EMS encourages property owners to mow their lawns and trim tall grasses, especially ones within 15 feet of homes, spokesperson Steve Lipsher said. Spending 30 minutes on a Saturday mowing grasses around a property could save a home if a fire comes through, Lipsher said. The National Fire Protection Association recommends keeping grasses mowed to under 4 inches tall, among other steps to make properties with yards more defensible.
“Just because we’ve had a significant amount of precipitation doesn’t mean that we can become complacent” Summit Fire & EMS wildland specialist Hannah Ohlson added.
The rain is likely to ease soon and temperatures will begin to rise, Ohlson said, according to Summit Fire & EMS’s temperature and precipitation outlooks. In the short term, Accuweather reported that a “heat dome” would fall over the region, and Summit County is expected to see a dry weekend, according to National Weather Service reports. Long-term predictions show similar trends, too.
“For July, August and September here in Summit County, we’re leaning below average for precipitation and are going to be likely in above-average temperatures for those same months: July to September,” Ohlson said.
Lipsher said the the combination of higher temperatures and drier weather can increase wildfire danger. Wet fuels will adjust to the climate, especially the light and “flashy” ones, Summit Fire & EMS Wildland Division coordinator Iseminger said. That means grasses and underbrush that saw rapid growth during the recent rain could quickly turn into dry fuel.
Iseminger said Summit Fire & EMS has seen an increased growth of fine fuels like grasses and brush, and sage brush fuels are nearing record highs.
But while the volume of biomass plays a role in wildfire danger, it isn’t nearly as significant as a fuel’s moisture level, Ohlson added.
Summit County will likely have a normal fire danger in July, August, September and October, Ohlson said. Iseminger stressed that normal fire danger does not mean there’s no danger — only that fire risk is as expected for Summit County.
Breckenridge’s station has yet to report its June precipitation numbers, but the National Weather Service reported the next nearest station — Williams Fork in Grand County — reported a slightly below average precipitation for June. So while rain may have seemed to increase, that may not have been the case. Precipitation averages in the Williams Fork area averages 0.99 inches in June, but only recorded 0.83 inches this year.
Why fire danger remains moderate, despite rain
Summit County’s fire danger remains moderate, despite near-daily storms for more than a week. While Lipsher said consistent rains have dampened some fuels, fire danger comes from several factors beyond the weather. Some wildfire fuels can take seasons to dampen or dry out. Wind can influence fire danger, as can the human element, Iseminger said.
Wildfire danger comes from a “conglomeration” of fuel types and weather data, Iseminger said. Some fuel types can dampen or dry out within an hour, like small brush and grasses. Those fuels will reach an equilibrium with the air’s moisture level quickly.
“Our one and 10 hour (fuels) can dry out and become available to wildfire in one to 10 hours,” Ohlson said.
As quickly as the rain can wet them, warm air and high winds can dry them out.
Other fuels like downed tree trunks can take thousands of hours to dry. Those fuels’ moisture levels react less to day-to-day weather and more to seasonal climates. They take longer to both dampen or dry, meaning they can sustain fire danger through periods of high precipitation.
“You can still have timber that’s really dry if you’re coming off of a drought year — or like a drought series of years,” Iseminger said.
“We also look at some of the other things like, do we have a heavy tourist population?” Iseminger said.
About 90% of wildfires are started by humans, Lipsher said, and their presence influences fire danger ratings.
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