The (new) water year of our discontent
The record low snowpack is likely to lead to record low streamflows
š„µ Aridification Watch š«
It was early June, and we sat out in the shade in our backyard in Silverton, Colorado, wearing short-sleeves and shorts and drinking cold beverages under a cloudless blue sky. That, in itself, made the day memorable. Blizzards are as likely on Memorial Day as barbecues in this mountain town, elevation 9,318 feet, and sweater-free days usually donāt come along until July.
The winter of 2001-2002 had been unusually mild and a warm April and May had melted what little snow had fallen; the Animas Riverās spring runoff had peaked at historically low levels a couple weeks earlier. I, for one, wasnāt too worried. By then it was understood that the climate was warming, and that it could wreak havoc on the planet, but the idea of rising sea levels and devastating heat waves felt pretty abstract in the Colorado high country. Besides, as an amateur historian, I had read accounts of similarly dry and warm winters from the San Juan Mountainsā past: In 1879, the snow was all melted from the highest peaks by May (giving way to the Lime Creek Burn that summer); sleighing was impossibleā on Silvertonās streets during the 1890-91 winter; and the newspaper ran a photo of a water wagon suppressing dust on Greene Street on New Yearās Day, 1918, during āone of the most delightful winters ever experienced.ā
This, it seemed, was just another one of those occasional weird years, so we figured we might as well enjoy it. Then someone noticed what looked like puffy cumulonimbus cloud rising up in the gap formed by the Animas River gorge. It wasnāt a cloud at all, but a billowing tower of smoke from the Missionary Ridge Fire, ignited that afternoon on a slope about 35 miles south of where we sat. Over the coming weeks, the blaze would eat through 73,000 acres of parched scrub oak and aspen and conifer forest, along with 83 structures. It eclipsed the 26,000-acre Lime Creek Burn as the stateās largest wildfire on record, but lost the title to the Hayman Fire (138,114 acres) that was burning at the same time across the state.
And it was then that we realized this was no normal abnormality, and that 2002 would go down as the Water Year of our Discontent: dry, smoky, and catastrophic for irrigators and river rafters alike.
This year is shaping up to be even more dire. Indeed, with temperatures in Silverton climbing into the 60s this week, Iām sure a few people have shed some layers and soaked up the sun ā in March. Now, however, we know that this is no anomaly, but part of a long-term trend toward aridification, most likely caused or at least exacerbated by climate change. Call it the ānew normalā if youād like, but just remember the words of Bruce Cockburn: āThe trouble with normal is it always gets worse.ā
I wanted to wait until April to give this assessment, on the off chance that the weather might shift radically in the last days of March in a way that might give us all some hope. While anythingās still possible, Iāve seen enough to bet that, unfortunately, we may already have seen peak snowpack in many places, making this the driest water year on record by far. And besides, I wanted to get the spring runoff āpredict the peakā streamflow contest going before, well, the streamflows actually peaked.
A crappy snow year does not necessarily lead to a nasty fire season, since so many other factors come into play. The same can sort of be true about the peak of the spring runoff. Thatās more about timing: A fast melt after a dry winter can result in a bigger, albeit short-lived, peak, than a slow melt of a relatively abundant snowpack. The riverās average flows across the entire water year are much more closely tied to snowpack, but those can also be affected by a big monsoon season.
Still, looking back at similar years in the past can help with predicting flows this year. Iām going to focus on the Animas River in Durango, because itās my home river, it is unimpeded by dams or major upstream diversions, and it is a good proxy for a lot of other Southwestern rivers, since its headwaters are located in the same mountain range as those of the Rio Grande, the Gunnison, the Dolores, the San Miguel, the San Juan, and the Uncompahgre rivers. If the runoff is weak in the Animas, it is also likely to be weak in all of those other rivers.
The snowpack graph shows that the current heat wave has really taken a toll, and probably launched the spring runoff.
Hereās the temperature graph for the Animas watershed. You can see that it reached a record high for the date of 42.8Ā° F. That doesnāt seem too warm until you consider that the median temperature for March 18 is about 25Ā° F. Probably more significant than this one little blip is the fact that daily temperatures have far exceeded ānormalā on dozens of days this winter. Also note the contrast with 2002 (the darker green line).
When you talk to Colorado climate folks and old-timers with good memories, youāll often hear that the 1977 water year was even drier than 2002. Unfortunately, SNOTEL records typically go back only to the early 1980s, so itās difficult to make a good apples-to-apples comparison. But by looking at the ānatural flowā of the Colorado River, which is the calculated estimate of how much the river would carry without any human intervention, it appears that 1977 was, indeed, the driest winter across the Upper Colorado River Basin since at least 1900.
However, historic Animas River flow data suggest that 2002 was actually drier in southwestern Colorado.
Hereās the average annual daily flow for the Animas. Note that there are several years missing between 1898 and 1911; apparently the USGS did not record flows during those years.
Because that graph isnāt so easy to read, hereās a table showing the eleven lowest average daily flow water years. Note that in 1927 they only had 92 records, potentially skewing the results. The 2002 and 2018 water years were lower than in 1977. If snowpack levels correlate with annual average flows, then we could expect this yearās to be around 200 cfs, which is pretty damned dismal.
When I took a look at the peak streamflows for the Animas, I was a bit taken aback to see that in 2002 it topped out above 1,000 cfs, which is more than I would have expected.
Then I saw the date: It peaked in September, after the monsoon arrived, not in the spring. The 2002 spring runoff actually topped out on May 21 at 880 cfs, which was far lower than the 1977 spring peak.
Based on all of that, my Animas River peak streamflow prediction is a bit wacky, but Iām standing by it: It will top out at 700 cfs on April 15.
The rest of the Land Desk community will have a chance to predict the peak starting next week, when Iāll announce the terms, the river gauges in the contest, and the prizes for the winner(s). Most likely it will only be open to paid subscribers, so the time to upgrade is now!
We might as well get even more depressed. Hereās the snowpack graph for the Upper Colorado River Basin, showing 2026, 2002, and 2018 ā i.e. the dismal years. Note that the spring melt has begun in earnest. If it continues at this rate, runoff will be over by early May.
And hereās the natural flow graph for Lees Ferry on the Colorado River. Natural flow is the calculation of how much water would be in the river at that point if there were no human diversions or consumptive use upstream. If you compare this to the historic streamflows on the Animas River, youāll notice that there is a correlation, but itās not direct. For example, 1977 was the driest year on record for the Colorado River as a whole, with a total volume of just 5.4 million acre-feet, which is about half what the Lower Basin alone was using throughout the 1990s.
The ten lowest years on record are:
1977: 5.4 MAF
2002: 5.9 MAF
1934: 6.6 MAF
2021: 7.2 MAF
1954: 8.3 MAF
2012: 8.4 MAF
2018: 8.5 MAF
2025: 8.5 MAF (provisional)
1981: 8.6 MAF
1931: 8.9 MAF
It looks like we could be in that 5.4 MAF territory once again. That wasnāt a huge deal in 1977, since it was an anomaly. It is a big deal now.
And just so you know, itās not just the Colorado River watershed thatās in trouble. Even California, which got pummeled by atmospheric rivers, is losing its snow rapidly.
š Reading (and watching) Room š§
The Upper Basin and Lower Basin may not have come up with a deal yet on how to save the Colorado Riverās massive plumbing system, but they are looking for solutions. One of them is creating an Upper Basin conservation pool. Like a lot of issues related to the rivers, itās a slightly complicated one. But Heather Sackett of Aspen Journalism gives a really great rundown. Sheās always a must-read for those looking to understand whatās going on with the Colorado.
šŗļø Messing with Maps š§
The current heat wave is breaking records across the West. Hereās a little sampling:
If you want a quick and comprehensive look where those records were broken during the last day, week, or month, check out coolwx.com/record. In the side panel you can click on the United States and the time period you wish to see and it will show an animation of all of the records. It looks kind of like this:
I appreciate your work. Thank you.
I learned to be a raft guide on the Arkansas in 1977. The river company shut down by July 4th. So little water! However, we learned how to run very technical water!