Eagle County’s best monsoon season in years has lowered fire danger, but drought still persists
Heavy rainfall in July and August cannot make up for below-average snowpack
Eagle County experiencing its best monsoon season in five years, accumulating over 4 inches of rain since July 1 according to trackers on both Vail and Beaver Creek mountain.
The past five summers have been characterized by hot and dry weather, with average rainfall hovering around 2 inches between July and August. That number has already doubled this summer, with more precipitation in the forecast this week.
The most substantial impact of a wet summer season is reduction of wildfire risk and the alleviation of drought conditions in the county. The heightened rainfall this summer has lowered wildfire risk considerably, with the Western Slope consistently categorized as experiencing “normal significant fire potential” by the Upper Colorado River Interagency Fire Management Unit since the end of June.
This is in sharp contrast to last summer, when over 80% of Eagle County was experiencing extreme and exceptional drought — the most severe categories — throughout the summer months.
The Colorado monsoon season, which officially starts on June 15, is created by abundant moisture that builds in the atmosphere from the Gulf of Mexico and the Baja peninsula area. Not only was this summer the most consistent in years, it also traveled the farthest north, covering most of the Rocky Mountain area all the way up to Wyoming.
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Most of Eagle County has reaped the benefits of this monsoon season, with all but the western-most part of the county experiencing above-average precipitation over the past 30 days and the mountains receiving 150-200% of average precipitation rates.
While the rains are a great benefit for mitigating drought severity in the region, Assistant State Climatologist Becky Bolinger said that no matter how much rain accumulates in the summer months, it cannot make up for poor snowpack. The water year, which is measured from Oct. 1 through Sept. 31, is primarily determined by how much precipitation is accumulated and stored during the winter months, and the summer rains are unable to put a substantial dent in the region’s unbroken 20-year megadrought.
“It’s more of a short term improvement rather than that bigger picture,” Bolinger said. “We will see a bump from those precipitation events, but overall, the cumulative flow that you need throughout the entire water year, the majority of that is going to come from snowpack melting.’
The cumulative water year, measured by total accumulated precipitation, has consistently trended below the 30-year median for the past decade. It has surpassed the average only once, in 2019, thanks to an influx of precipitation in March and April that resulted in substantial snowpack. The summer rains have already raised the 2022 water year above the previous five years that started with weaker snowpack, but is a full 8 inches less than 2019.
“You can’t really make up that deficit in terms of the hydrology of the region,” Bolinger said. “These are drops in the bucket.”
Similarly, the shortage of water supply in state reservoirs is only slightly helped by the summer rains. Russ Schumacher, the director of the Colorado Climate Center, said that the summer months always see the highest consumption of reservoir resources, and a good monsoon season mostly serves to slow demand rather than replenish supply.
“What it does is it reduces the drawdown of the reservoirs in the summer because there’s not as much demand — irrigators don’t need to put as much water out, and people just aren’t using as much water because they’re getting free water from the sky,” Schumacher said. “So it’s helpful in that sense, but it’s not nearly enough to make any dent in the long term deficit.”
One of the major benefits of a wet summer season is that it can set the next water year up for success. Soil moisture levels heading into the winter have a direct correlation with snowpack levels in the spring. Whatever moisture level the plants and soil freeze at determines how much water they will require when the snow melts, with dry soil acting as a debt to be paid before the water can reach the rivers and reservoirs.
“It’s certainly much better to have an active monsoon season like this year than some of the ones we’ve had in the recent past because it recharges the soil moisture, which is really important once we get to the snow accumulation,” Schumacher said. “The snow starts to build up on soils that are wetter, and when the snow melts in the spring, it doesn’t have to recharge those soils because they already have good moisture in them.”
If soil moisture levels can remain high through the fall, the opportunity for a good 2023 water year is much improved, but these conditions may be thwarted by a third consecutive year of La Niña conditions. During La Niña, cold waters in the Pacific push the jet stream northward, intensifying drought conditions in the southern U.S. This is only the third time since records began being kept in 1950 that La Niña weather patterns have persisted for three years, and Bolinger said it has been manifesting in Colorado with particularly dry fall seasons.
While it would be nice to equate heavy rain with overcoming long-term drought conditions, the true equation is not that simple, and Bolinger noted that particularly in Colorado, conditions can turn on a dime. That said, this summer has been a welcome reprieve from wildfires and dry conditions, and better positions the county to face a dry fall.
“We’ve had two La Niñas in the past two falls, and both times that has turned us into this hot, dry pattern in the fall that kind of chipped away at that strong start,” Bolinger said. “But neither of those years, or even the past four or five years, have had as good precipitation in the summer as what we’ve seen this year. Depending on what we see happen in September and October before the snowpack starts to set in is really going to dictate it. But so far it’s looking good.”