Graphical representation of Colorado’s warming since 1895, from the Institute for Environmental Analytics. You can download stripes for most of the world.
From the Middle Colorado Watershed Council (Erika Gibson) via The Glenwood Springs Post Independent:
Everyone is talking about snowpack this year. The news boasts epic-sounding statistics for snowpack that is “649 percent of normal,” “128 percent of average,” “440 percent of median,” or, my personal favorite, “1,776 percent of last year.” One need not speak math to know that big snowpack is generally a good thing. But unpacking the statistical lingo can help in understanding what those numbers actually indicate.
People generally understand snowpack to refer to snow depth. But in the context of water supply, snow depth doesn’t matter as much as snow-water equivalent. SWE is the amount of liquid water released when snow is melted instantaneously. SWE data mainly comes from automated sites across Colorado that capture, record and report daily data.
SWE is a more useful measurement for understanding water supply than snow depth, because water content in snow layers can vary — consider the difference between two inches of wet, heavy snow and dry powder. And when discussing snowpack, what most people care about is not cubic inches of snow in the mountains; it’s how much water will flow through our rivers, ditches and reservoirs.
This year, peak SWE for the Upper Colorado Basin was 20 inches. To add context, last year, which was dry, the SWE was 16 inches, while in the 2011 flood year it was 25 inches.
Snowpack varies throughout the year. Imagine a mountain profile where the left side is an easy, long slope that steps up to a series of peaks, and the right side is a steep, jagged descent. This is what the actual SWE data looks like plotted for each day as snowpack starts to build in October, slowly accumulates through the winter, peaks in April, then starts to melt (with some intermittent, spring-storm gains) though June or July when it’s fully depleted.
When most people bandy snowpack statistics around, they are referring to a point on that graph and “average” is probably the most confused term that gets used. We typically understand “average” to mean the arithmetic “mean,” which is the sum of numbers in a set divided by the number of numbers used in the set. (For example, the mean of 4, 6 and 20 is 10). But when discussing snowpack, the “average” typically refers to the median, which is the number that falls in the middle of the set. (So, the median of 4, 6 and 20 is 6.) In other words, there are different ways of describing what is “normal.”
Snowpack averages most often compare a relevant date of the current year to the median value on that same date within the study period (for western snowpack, the dataset is from 1981 to 2010). The median is more appropriate because it is not affected by outlier years.
You can see on an SWE graph that the median snowpack is less than the mean snowpack. This means there have been more low-snow years than high-snow years, but the high-snow years were really snowy, thus skewing the mean higher and the median lower.
Anyway, math schmath. … What most people really care about isn’t the difference between median and mean. People care about how much water there is. We want to know when the rivers will really start to flow, whether they’ll flood, and when runoff will peter out. And the relationship between snowpack and runoff has almost as much to do with the timing and intensity of spring and summer weather as the timing of peak SWE.
For example, because of spring-weather timing, runoff this year is late and expected to be sustained for longer. Peak snowpack also occurred later, and temperatures are staying cooler, so runoff is expected to peak in late June. Compare that to 2011, another heavy snow year, where warmer weather and rain caused runoff to peak in May, with more flooding.
This year’s snowpack-generated runoff is good news for water users now, but how good is it for the future? It will recharge the soil and aquifers, refill reservoirs, make for long recreation and irrigation seasons, and help mitigate Colorado’s long-term drought.
However, this region has been in a 16-year drought and needs several more years of increased snowpack and cool temperatures to alleviate the pressures on regional water supplies. According to Colorado River District engineer John Currier, we will need at least seven consecutive 2019s to fully fill lakes Powell and Mead, which are currently at historic lows.
Understanding snowpack, in sum, has more than some depth to it.
Erika Gibson is a contributor to this monthly column for the Middle Colorado Watershed Council, which works to evaluate, protect and enhance the health of the middle Colorado River watershed through the cooperative effort of watershed stakeholders: anyone standing in the watershed. To learn more about the MCWC, visit https://www.midcowatershed.org. You can also find the Council on Facebook at https://www.facebook.com/midcowatershed.
From Aspen Journalism (Brent Gardner-Smith):
The Colorado River east of Grand Junction in DeBeque Canyon is forecast to hit its annual peak Saturday, in a quick climb to about 21,000 cubic feet of water per second, as measured at the Cameo gage, before dropping over the next week as cooler weather arrives.
The operators of five upstream reservoirs have been closely watching this season’s large, and late, spring-runoff pattern, and they are now starting a coordinated release of water designed to improve habitat for endangered fish in a 15-mile stretch of the river below Palisade.
The reservoir releases, which collectively will add about 1,300 cfs of water to the river, are being timed to reach Palisade on Monday or Tuesday, after this weekend’s peak flows have subsided.
The goal of this year’s coordinated release of water is to extend the high flows, not add to the peak flow, as it is in most years, said Don Anderson, a hydrologist with U.S. Fish and Wildlife, who said care is being taken not to increase the risk of flooding this weekend.
The releases from Ruedi, Homestake, Wolford, Williams Fork and Green Mountain reservoirs are designed to benefit four ancient species of fish.
The well-timed higher water will send spawning cues to Colorado pikeminnows, large powerful fish that swim upstream to spawn in the gravel beds of what’s known as “the 15-mile reach.”
Higher water will give the recent offspring of razorback suckers a chance to find refuge in calm side channels.
Higher, faster water will scour fine silt from gravel beds, flush away dry-year vegetation growth and help the river absorb nutrients from wet floodplains.
And the high water will also benefit populations of humpback chubb downstream of Grand Junction — at Blackrocks, in Westwater canyon and near Moab — and may also help the struggling bonytail chubb.
As part of this year’s effort, the outflow from Ruedi Reservoir into the lower Fryingpan
Reservoir will rise Sunday by 100 cfs, and over three days, the releases will climb from 354 cfs to 630 cfs or above, before stepping back down Wednesday.
The flow from Rocky Fork Creek, which runs into the Fryingpan below Ruedi Dam, was adding 75 cfs to the river Friday, which means the ’Pan could be 700 cfs or above by Tuesday or Wednesday.
Tim Miller, a hydrologist at the Bureau of Reclamation, said a flow of about 700 cfs is consistent with most of the other 10 years since 1997 that Ruedi has participated in what is called the Coordinated Reservoir Operations, or CROS, program.
Miller’s operational goals with this year’s CROS program include keeping outflow from the reservoir below inflow, so he can fill the 102,000 acre-foot reservoir in early July, while keeping flows in the lower Fryingpan below 850 cfs.
Releases from Homestake Reservoir, which is on Homestake Creek in the Eagle River basin and is managed by Aurora and Colorado Springs, are going to climb in a similar timeframe as Ruedi’s, moving from 6 cfs to 100 cfs Monday and then stepping back down to 6 cfs by week’s end, according to a summary of the expected releases from the Colorado River Basin Forecast Center.
Releases from Green Mountain Reservoir, which is on the Blue River north of Silverthorne and managed by Reclamation, are slated to rise from 800 cfs to 1,400 cfs and then drop back down.
Releases from Williams Fork Reservoir, which is on a tributary of the Colorado east of
Kremmling and managed by Denver Water, will increase from 350 cfs to 650 cfs and then drop.
And Wolford Reservoir, on Muddy Creek north of Kremmling and managed by the Colorado River District, is currently spilling about 400 cfs of water due to high inflows. The River District regularly participates in the CROS program, but this year is spilling water in any event and not releasing water just for the CROS program as it often does.
During a series of conference calls over the past several weeks, reservoir managers have
described this year’s snowpack as “bashful” and “tentative” and “well-behaved” due to colder temperatures in May and June. And while the snow is still deep in the Colorado River’s headwaters, more cool weather is in the forecast.
And every water manager sounds glad there is at least water this year to run after last year’s deep drought, and most now expect their reservoirs to fill, which gives them flexibility this week to release water for the fish and for the river.
This year’s high flow — 21,000 cfs, forecast for Saturday — is the opposite of last year, when the Colorado peaked, as measured at the Cameo gage, on May 19 at about 6,800 cfs.
From The Durango Herald (Jonathan Romeo):
As the Animas River approaches peak flow, concerns are being raised that the city of Durango created a hazard when it added two new rapids to the Whitewater Park, resulting in many rafting companies choosing to bypass the park for safety reasons.
“It’s an unnatural hazard at the entry of the park, and it creates a rafting experience we’re not selling to our guests,” said Alex Mickel, owner of Mild to Wild Rafting & Jeep Tours. “It’s just been unfortunate.”
Since the 1980s, the city has made tweaks to the Whitewater Park, which flows alongside Santa Rita Park.
But in summer 2016, the city spent $1 million to create two new features just above the park with the sole purpose of diverting more water into the city’s water intake for municipal use.
It’s these new features that are drawing criticism and concern as the Animas River rises to higher-than-normal flows for the first time since the ledges were built. As of Friday, the river had usurped 6,000 cubic feet per second (the Animas usually peaks at around 4,700 cfs).
“They’re manmade nightmares,” said James Wilkes, co-owner of Mountain Waters Rafting. “They’re just not natural, and it’s very difficult for a raft to pass through it.”
From American Rivers:
Water and wheat — foundations of life for millennia. In the American Southwest’s arid Sonoran Desert, water flows across Arizona from more than 300 miles away to quench the thirsts of more than four million people and sustain the food, economy, and livelihoods they rely on every day. Join us as we explore the thoughts of three visionaries in Tucson who are creating and growing a circular economy of water, forging a sustainable future for a city that could have gone in another direction. And nearly did.
We hear from third-generation farmer Brian Wong, who grows a variety of low-water and heat tolerant organic heritage wheat in the arid plains northwest of Tucson, and Don Guerra of Barrio Bread, who bakes 1,000 loaves of artisanal bread per day using local and indigenous wheat varieties. Brian and Don are bound together by water and the City of Tucson’s ability to provide it to them, and their community. Lastly, we hear from Tim Thomure, director of Tucson Water — a visionary working to build and sustain a thriving city in the Sonoran Desert.
American Rivers is deeply involved with a number of efforts across Arizona to help sustain the lives of millions of people across the state, ensure the viability of a thriving economy in the desert, as well as protect the vital lifeline for the entire region, the Colorado River.
Join us as we explore these ideas, and others, across the Southwest. For more information about this work, please see our Lower Colorado River page, and follow us to keep in touch with what is going on across this important region of the country.
Zach Ruffert on trumpet.
From The Denver Post (Elise Schmelzer):
Lake City, the only town in remote Hinsdale County, is one of many rural Colorado communities working to prepare for potential flooding as the winter’s epic snowpack begins to melt. Mountain towns across the state are preparing sandbags and warning visitors about high water…
Although numerous mountain towns have prepared for high water, Lake City’s predicament was particularly dire and threatened lives before the emergency crews arrived, state officials said.
More than 60 avalanches, some more than a half-mile wide, pushed mountainsides of trees, boulders and snow to the floors of the two river valleys surrounding the town, which sits at the confluence of Henson Creek and the Lake Fork of the Gunnison River…
Authorities feared a wall of water could build if the logs jammed or blocked one of the two historic dams. If the debris jam or dam were to break, the surge of water sent downstream could send feet of water into some of the low-lying areas of town within 15 minutes.
At a town meeting Tuesday, officials estimated there was a 10 percent chance that the worst-case scenario could happen if weather conditions aligned perfectly and predicted that high water could begin as early as this weekend. Federal, state and local officials have worked in the city for a few weeks to mitigate the chance of such a surge, including partially deconstructing one of the dams…
Lake City residents knew the avalanches around their town of about 400 people this past winter were unprecedented. The avalanches in February and March caused voluntary evacuations and flattened the Hinsdale County sheriff’s house outside town.
But it wasn’t until crews in April started exploring the two mountain roads along the river valleys that the size of the avalanches became apparent. Piles of centuries-old trees, snow and boulders covered sections of roads up to a half-mile long…
Mitigation efforts have been broad. Personnel from the group of agencies built a berm along one of the rivers in town. They partially destroyed one of the historic dams so water could flow better. They also placed additional sensors along the rivers so the flows could be monitored in real time. They helped organize the filling and deployment of more than 18,000 sandbags around town to protect important buildings. Crews surrounded the most vulnerable homes near the confluence with 3,000-pound mega sandbags…
Engineers recommended that the town demolish the 129-year-old Hidden Treasure Dam because they worried that avalanche debris could block the dam and cause it to fail, sending a rush of water toward town. Contractors used a remote-controlled jackhammer suspended on a sling to chip away at the top of the dam and small explosives to blast away the bottom.
But engineers later determined the new gaps at the top and the bottom were big enough to avoid a jam…
Signs along the Rio Grande on Wednesday prohibited anybody — or any boat — from entering the raging water. Along Colorado 149, the river overtook tree trunks and washed out boat ramps, but left houses untouched. Campgrounds and some roads in the area remained closed.
Mineral and Rio Grande counties, as well as sections of Conejos and Saguache counties, remained on flood watch Thursday. Officials in Chaffee and Summit counties, as well as the towns of Silverthorne, Buena Vista, Avon and Ouray, have opened sandbag stations…
In Creede, about 50 miles southeast of Lake City, waters have taken over the floodplain but haven’t threatened any structures, said Kathleen Murphy, director of the town’s chamber of commerce. The city worked last week to widen a concrete flume that directs water through town. A road north of town washed out after avalanche debris built up, releasing a surge of water. Some lower-elevation hiking trails were flooded as well.
From The Summit Daily News (Allen Best):
In Colorado, where snow still blankets the San Juan Mountains, the Durango Telegraph has proclaimed El Niño as the winner of this year’s Hardrock 100. The race was scheduled for mid-July.
Organizers canceled the 100-mile foot race among the peaks of the San Juans around Silverton owing to “unprecedented avalanche debris, unstable snow bridges and high water” that compromised 40 miles of the race course.
It was the third time in 27 years that the race had been canceled, the first being in 1995 because of too much snow and then in 2002 because of forest fires.
At the California Weather Blog, meteorologist Daniel Swain suggests a big view of weather extremes across North America: floods in Nebraska, tornadoes in Oklahoma, a massive forest fire in Canada and record heat in the Arctic. They’re all connected, he points out.
Emerging evidence suggests that such weather extremes may be occurring with greater frequency and intensity as the Arctic continues to warm faster than the rest of the planet.
“Interestingly, though, this doesn’t necessarily mean that the impacts we experienced in 2019 will be exactly the same the next time this pattern repeats,” Swain wrote on his blog. Every iteration of the “wavy jet stream” produces new patterns of warmth vs. coolness and very wet vs. very dry.
From KOAA.com (Tyler Dumas):
The Arkansas River keeps rising in Fremont and Pueblo Counties.
10 feet is considered flood stage in Canon City and the river reached that level at 8:30 a.m. Saturday morning. Minor flooding is expected in flatter areas, like along Raynolds Ave.
In Avondale, flood stage is considered 7 feet, which was reached around 11 p.m. Friday night…
Parks and Wildlife has closed off the river below the dam at Lake Pueblo State Park to swimmers and all non-whitewater boats, including inner tubes and kayaks.
Law enforcement in Pueblo has also closed off the river east of Pueblo Blvd. to the Otero County line because of fast-moving water.
From InkStain (John Fleck):
The Bureau of Reclamation’s monthly storage model runs, based on the latest Colorado River Basin runoff forecasts, show Lake Powell ending the water year (Sept. 30) at 13.8 million acre feet. That’s an increase of more than a million feet over the May estimate, and 2.8 million acre feet above the Sept. 30, 2018 number:
From email from Reclamation (James Bishop):
Releases from Green Mountain to the Blue River will increase according to the following schedule starting at midnight [June 15, 2019] (cusp between 15 and 16 June):
12:00 a.m. Adjust release from 1100 cfs to 1200 cfs
3:00 a,m. Adjust release from 1200 cfs to 1300 cfs
6:00 a.m. Adjust release from 1300 cfs to 1400 cfs