SUMMARY
Water Year 2026 will be etched in everybody's memory for the rest of time. Even if you never concern yourself with snow, water, weather, anything happening outside, you will remember this water year. Our notion of “normal” was completely uprooted and the warning by climate scientists when they saying “we are in uncharted territory” begins to really sink in, this climate change really means a changing climate.
Maybe the concerning question is, “was WY2026 the first year that ushered in a completely different and unrecognizable climate norm”? Not just warmer or drier than average, but extreme changes that we did not have the imagination to contemplate. We’ve been seeing the affects of climate change coming at a rapid pace, particularly over the past 25 years we’ve really seen it take hold. It is thought that this dry winter was four times more likely to happen due to climate change. In hindsight will the megadrought these past 26 years seem like the idyllic days we long to get back to?
WY2026 is also etched in the data record, thermometers don’t lie, neither does the snowpack when we visit the same spot to take measurements for the past 10, 20, 50, 100 years. And this is what we do here at Center for Snow & Avalanche Studies. We collect the data, make the observations, and assess what it all means. And this year there is a lot to digest.
The water year began in October and in that month southwestern Colorado was hit with one of the largest rainfall events ever recorded that caused widespread flooding. Record heat and dryness followed resulting in our documenting the first storm of the winter about 3 weeks later than usual. It was still so warm in December it rained on Christmas day in Silverton and many other high elevation locations around Colorado. And it persisted, remaining hot/dry for the remainder of what is usually the snowy months.
MONTHLY WEATHER CONDITIONS
October
The first month of the water year brought one of the largest rainfall events ever recorded in southwestern Colorado, with totals from 2-4+” in two days, remnants of a hurricane in the eastern Pacific Ocean. Drought conditions in the southwestern Colorado saw a 2 to 3 class improvement, though we would have preferred this amount of rainfall over a few weeks.
October was warm for the state of Colorado as a whole, continuing a trend, with areas of more than 4°F above average observed. At Swamp Angel Study Plot (11,060’), snow fell in the higher elevations during the month, but did not stick around. The average temperature at Swamp Angel was 36.9°F. We began this water year with La Niña conditions which were expected to continue through early winter before returning to neutral.
November
November was extremely warm throughout the state of Colorado, the 3rd warmest on record in 131 years of records. Precipitation was below average for much of the state, except the San Luis Valley and the eastern Plains.
Our first official winter storm arrived November 15th at Swamp Angel, which is two to three weeks later than the median first storm date. At the end of month, we had 9.8” of snow depth at Swamp Angel, with 1.9” SWE and an average monthly temperature of 30.0°F.
December
In December, the unusually warm temperatures started to really feel weird. The Colorado Climate Center reported over 1000 daily max temperature records were set statewide. Not only was it hot, it was dry; and the precipitation that did fall was rain at much higher elevations that is typical. In Silverton, it rained on Christmas day. Swamp Angel broke daily maximum temperature records for eight days in a row from 12/19 through 12/26. Snow depth at the end of the month: 20.9”, SWE 5.4”, and the average monthly temperature was 24.6°F.
January
Temperatures in January were warmer than average in most parts of the state, continuing the trend. To kick off the month, it rained in Silverton on New Years Day. Despite the warm temperatures, we were hopeful for a ‘pattern change’ and the snow to really pick up and stay up for the rest of the year. However, though January was snowier than previous months, the extremely low snowpack did not make many gains, and state of Colorado percent of median SWE dipped into record-low territory towards the end of January. Snow depth at Swamp Angel Study Plot at the end of the month was 35”, SWE was 8.1”, and the average monthly temperature: -18.1°F.
February
Colorado had the warmest February of the last 132 years with temperatures 7-9 degrees above normal. The state of Colorado snowpack was determined to be the lowest in 40 years. In the southwest, we had a few winter storms but the scale of the deficit was too big for those storms to be very meaningful. Most watersheds in Colorado ended the month with 60-70% of median SWE, and the lowest was the Arkansas River Basin which had only 46% of median SWE. Some stations in the southwest of Colorado hit peak SWE at the end of February.
Swamp Angel Study Plot hit a peak snowpack depth of 56” on February 20th. Notably, there were no dust events to record yet this winter, a rare occurrence. Snow depth at the end of the month was 45” with 11.7” SWE and an average monthly temperature: 23.5°F.
March
March followed in February’s footsteps and became the warmest March on record for the state of Colorado. In our part of the state, the sun and heat felt relentless, and evening air temperatures at Senator Beck station (12,186’) were above freezing while Swamp Angel (11,060’) was only a degree or two below freezing. The prolonged lack of precipitation kicked snowmelt into drive and SWE plots across the state nose-dived, resulting in an uptick in streamflow in many rivers which we thought could possibly be peak flow. Snow depth at the end of the month had decreased to just 20” with 7.0” of SWE. The average monthly temperature was above freezing, at 33.3°F.
April
We did our second CODOS tour at the turn of the month finishing April 3rd, rather than the second week of April, which on a more normal year would capture conditions close to peak SWE. This year, we were flirting with snow all gone at many of our sites, and therefore mobilized to collect our dust samples before that happened. Conditions were a month and a half ahead of the normal schedule. Some faint buried surface dust was found in the snowpack at Berthoud, Loveland, and Rabbit Ears. Some sites, including Grand Mesa, had surface dust.
We received the pattern change we were hoping for as April progressed, but no season-saving snowstorms arrived. Instead, in the southwest, we had overcast weather, some precipitation, and more normal temperatures. This stalled the nose-dive of SWE plots and returned streamflows to holding steady or slightly declining.
Snow depth at Swamp Angel at the end of April was just 13”, with 6.5” SWE, and an average monthly temperature of 30.2°F.
May
While southwestern Colorado was still warm, the rest of the state of Colorado finally got back to more normal temperatures. A few days into May, the dry conditions returned, especially in the southwest, and we saw streamflows rise and peak as the rest of the snowpack sped towards melt-out after the April stall-out. A couple of our CODOS sites saw decent snowstorms in the central mountains, but the rest continued their melt-out.
Snow all gone at Swamp Angel was May 13, the earliest date in our 22-year record. The dust season remained the mildest on record, with the only distinct layer present in the Roaring Fork and Grand Mesa region. Very mild surface dust was observed at other sites, some of those dust sources were likely more local. Average monthly temperature at Swamp Angel was 38.8°F.
June/July Weather Summary: June was warm and usually dry. Multiple forest fires kicked up across the Western U.S. Fortunately the monsoons arrived mid-July benefitting southern Colorado the most but all of Colorado to a degree as of his writing.
Below: Images of the WY2026 snowpack. For most areas peak SWE was around the first of March thru mid-March. So most pictures are showing a peak snowpack.
Below: Soil moisture conditions going into winter for the last four years. The beginning of WY2026 soil moisture was better in the southern part of the UCRB than the previous year in general due to the heavy rain in October. Healthy soil moisture conditions generally improve the likelihood of more efficient snowmelt runoff.
Above: The southern basins had a strong start to the season and held on until about January then started to fall behind and couldn’t catch up. Northern basins held near median levels up until about April and then started falling behind normal precipitation accumulation.
SENATOR BECK STUDY BASIN DATA
This section describes conditions and data collected by the Center for Snow and Avalanche Studies at our Senator Beck Basin Study Area (SBB) at Red Mountain Pass under our Mountain System Monitoring program, which includes the Colorado Dust-on-Snow Program (CODOS). At SBB, snowpack, weather, soils, and radiation conditions are monitored and measured at the well-sheltered subalpine Swamp Angel Study Plot (SASP, 11,060’) and at the more exposed, alpine Senator Beck Study Plot (SBSP, 12,180’). Nearby, wind speed, wind direction, air temperature, and humidity data are collected at the Putney Study Plot (PTSP, 12,323’), located to minimize the influence of local terrain on those measurements. Finally, SBB streamflow discharge is continuously measured at the SBB pour point at the Senator Beck Stream Gauge (SBSG, 11,030’), in a broad-crested, notched weir.
All total we received 20 storms, just under average for our season. A storm is defined as receiving 12 mm (0.5”) or more of precipitation with no break in precipitation greater than 12 hours. Winter storm reports can be viewed at the snowstudies.org website.
The above graph shows precipitation at SASP with snow depth at SASP and SBSP. Early precipitation helped soil moisture and started the snow accumulation season in fine fashion. Productive storms tapered off latter January and really got bad starting in April. The first half of June was wet through the state except the northwest corner, the first two weeks of June some areas were over 400% of normal.
Above: Water Year 2025 cumulative precipitation.
SNOWPACK CONDITIONS
This winter started off with a bang for the San Juans, with the first snows hitting October 16th and lasting four days, delivering 2.7” of snow water equivalent and a foot and a half depth. Another late October storm set many of the lower basins up 200% of normal SWE heading into November.
We kept the lead through November, with two more storms and 115% of normal precipitation at Swamp Angel. A major snowfall event occurred in the southeastern mountains of Colorado in November as well, which kept the central and southern half of Colorado with a higher snowpack than the northern mountains, which were hovering shy of average heading into December.
Just as we were making winter interlodge plans in town, December took a warm and dry turn, which lasted all the way until the holidays. Two mild, consecutive snow storms hit the San Juans the last week of the month, and overall, most Colorado basins were at or just below average SWE conditions for the start of the new year. In January, the southern basins began to lose their foothold on a decent snow year. On January 1st, SWE % of normal was as follows: Upper San Juan – 77%, Rio Grande – 83%, Gunnison – 102%, Dolores – 99%, Arkansas – 106%, and Upper Colorado Headwaters – 103%. On February 1st, SWE % of normal was: Upper San Juan – 61%, Rio Grande – 72%, Gunnison – 85%, Dolores – 77%, Arkansas – 91%, and Upper Colorado Headwaters – 93%. Once those lower basins started to fall behind, they never caught up. We just didn’t have the precipitation needed to make a comeback.
For Swamp Angel, our low precipitation started in December which was just 54% of the average, while January was 53% of average. February was 76% of normal and even though March precipitation was above average (118%), it wasn’t enough to catch us up from three significantly dry months. And even though March delivered somewhat, we also had some very warm temperatures. The spring sun baked us, alternating with a few brief snows, through April. The albedo reset delivered by bits of snowfall was very welcome. Nevertheless, SWE conditions headed south, unable to stand up to that spring sun and warm/dry air. There were a few very small nooks, such as our Senator Beck station, at higher elevations above treeline that accumulated more snow and held onto it pretty well compared to the lower elevation stations. With just a few stations in the high alpine in Colorado, it can be difficult to know what is going on up there, making stations like Senator Beck a very valuable resource for water managers and forecasters.
On May 1st, the NRCS Basin SNOTEL map had far too much lobster red (<50% SWE) and sunset oranges to leave any of us with much hope for a sustained streamflow season. Going into May we played the ‘predict the peak’ game following the lead of years like 2018 and 2012 to inform our guess of peak flow in the local adjacent watersheds. Fortunately at least, timely storms in May and first of June provided cloudy/cool conditions and modest albedo resets which prolonged snowmelt enough to make the peak flow around June 1, a bit closer to the average peak timeframe for most basins.
Above: All major basins struggled this season but there was yet again a north/south split that we have seen numerous occasions in the recent past, where northern basins fared significantly better than the southern.
Above: Annual statistics for individual SNOTEL stations tracked by the CODOS Program.
Below: Summary statistics for individual SNOTEL stations.
Below: Summary data for WY2025 at the 16 SNOTEL stations that CODOS monitors. The table shows peak SWE, and calculated from the day of peak SWE, melt rates, days to snow-all-gone, and mean temperature. Grizzly Peak (Loveland Pass) and Berthoud fared the best at 115% and 102% of normal. All other sites were below normal. The Rio Grande and San Juans as a whole came in on the low end.
Below: A summary of WY 2006-2025 snowmelt rates and associated conditions at the 16 SNOTEL stations that CODOS routinely monitors. Days to SAG refers to the time between peak SWE and “snow all gone” at the SNOTEL sites. Adjusted Daily Mean Loss calculates the rate of snowmelt following peak SWE, including all precipitation received after peak SWE (assumed to be snow). Melt rate tables are presented for each of the 11 CODOS monitoring sites on their webpages.
Group mean peak SWE was about average. The adjusted daily loss of SWE was on the low end.
Above: Snow depth at Swamp Angel Study Plot.
Above: Snow depth at Senator Beck Study Plot.
Above: Snow water equivalent at Swamp Angel from snow profiles.
Above: Snow water equivalent at Senator Beck Study Plot from snow profiles.
DUST-ON-SNOW CONDITIONS
DUST ENHANCED RUNOFF CLASSIFICATION:
In Water Year 2015 CODOS introduced a Dust Enhanced Runoff Classification (DERC) approach to linking dust-on-snow, snowpack, and spring weather conditions to patterns in statewide hydrographs within a 3x3x3 Dust Enhanced Runoff Space. The below table presents the final DERC classification of WY2025 parameters at each of the 20 stream gauges monitored by CODOS. Water Years 2006-2025 classifications are contained in Excel workbook Runoff_Space_by_Region_and_WY.xlsx. Another workbook, Runoff_Space_by_Watershed.xlsx, contains individual DERC analyses for WY 2006-2025 for each of the 20 stream gauges.
A conceptual Dust Enhanced Snowmelt Runoff Space integrating the interactions of March 1 SWE, dust intensity, and spring precipitation.
Current and prior seasons snowpack conditions, dust severity, and spring precipitation are mapped for individual DERC space along with the hydrographs. These analyses are presented in PDF format and are available for the watersheds listed below. Referencing these DERC spaces in spring is helpful to get and idea how spring runoff will possibly unfold.
Below: Based on the discussions describing the DERC approach in characterizing the watersheds that CODOS monitors, WY2025 snowmelt season conditions are summarized in the tables below. Essentially, Colorado WY2025 snowpack and snowmelt runoff behaviors were mostly average with a number of wetter and drier areas. Dust severity was about minimal throughout Colorado but a dry/warm wet spring largely kept dust on the snow surface with an occasional storm temporarily covered the surface helping push runoff towards a more normal time period. Volumes however were very low.
This year was a mild year for dust-on-snow in Colorado. We tracked more than one dust plume on satellite imagery that skirted south of the Colorado mountains sparing us from having a dustier snowpack. The number of near-misses helped solidify this season as a mild year for dust-on-snow. Here, we discuss the progression of the dust season in Colorado.
The Senator Beck Study Basin received approximately three dust events this season. Often, dust layers were faint in the snowpack, at times not revealing themselves until the snowpack had settled and densified as the season progressed. We’ve documented three events – D1 (Dust Event #1) occurred on January 25-26th, D2 on March 18th, and D3 around April 1st.
The weekend of January 25-26th we had reports of winds picking up and visible dust on the surface of the snow on Red Mountain Pass. On January 25-26th, prevailing winds were from the south, with the highest windspeeds occurring the afternoon/evening of the 25th. The following week on January 29-30th, Swamp Angel received some precipitation, accumulating 13 cm (5”) of depth. And in our Jan 31st pit we found a dust layer approximately 5” below the surface, which means the dust was a dry event (airborne dust without any precipitation) that blew in before that Jan 29th snowfall.
For our March dust event, we located a plume of dust kicking up on satellite imagery over land with no/low vegetation cover in Utah, and drifting west/southwest towards the San Juans. In the afternoon/evening of March 18th, we had direct westerly winds with gusts up to 66 mph. We speculate the dust blew in right in front of the storm, then followed 1.1” of liquid precipitation landing March 18-19th. On March 25th, we dug a pit and located a dust layer about 13” below the snow surface.
The transition from March into April had another dust event in store. The April 1-3rd snowstorm brought just over 11” of depth and 1.7” of SWE. About 10” of fresh snow sat atop the new dust layer in the April 4th Swamp Angel pit, so the dust likely blew in during the first part of the storm, where our plots also show was the windiest with prevailing winds coming from the west/southwest.
At the time of the first dust-on-snow tour of the season, March, we had only observed one dust event hitting the mountains from the January event. The distribution of this dust was somewhat typical. Generally, the southern mountains pick up quite a bit more dust. During our March CODOS tour, two southern sites had two established dust layers (Swamp Angel, Wolf Creek) while some of our central mountains (McClure, Grizzly and Hoosier) had faint dust evident. The northern sites’ snowpacks were dust-free, as was Grand Mesa, the western-most central site.
After the first week in April with all three dust events of the season under our belt, all southern sites had light dust, with Wolf Creek and Swamp Angel still the most significant, though still mild compared to what we’ve seen in the past. Berthoud Pass in the central mountains remained dust-free, while Grand Mesa, Grizzly, and Hoosier all had one dust layer mid-snowpack and McClure had dust 2” below the surface of a shallow snowpack. In the northern mountains, Rabbit Ears had two layers, one 42” below the surface, which was perhaps a consolidated layer from earlier in the season that wasn’t visible before, and another very mild dust presence 11” below the surface. Willow Creek, east of Rabbit Ears by thirty miles or so, had no visible dust.
Warm temperatures made our May CODOS tour less exciting – due to no snow, no pits were dug at Wolf Creek, Spring Creek, Park Cone, and McClure, though we sampled merged dust at the surface of the snow in the remaining patches. Grand Mesa and Hoosier had dust layers merged at the surface, while the snowpacks of Berthoud and Grizzly enjoyed a fresh topping from a May snowstorm, where we found the merged dust layers below the new storm slabs of 29” and 15”, respectively. Rabbit Ears still had mild dust mid-pack, and holding, but missed out of the surface refresh.
March CODOS Summary
Swamp Angel had one dust layer from the January 31st storm at about 29” below the snow surface
Park Cone no dust observed
Spring Creek no dust observed
Wolf Creek had two mild dust layers
Grand Mesa no dust observed
McClure had faint dust 2” below the surface of a 31” deep snowpack
Hoosier had faint dust 12” below the surface
Grizzly Peak had faint dust 24” below the surface
Berthoud no dust observed
Willow Creek no dust observed
Rabbit Ears no dust observed and over 6’ of snow
April CODOS Summary
Swamp Angel had dust 34” below the surface, another layer at 18” below the surface, and a lighter layer at 11” below surface
Park Cone had light dust/debris at the surface
Spring Creek had very light surface dust
Wolf Creek had two darker dust layers, and a shallow pit for this time of year
Berthoud Pass no dust observed
Grand Mesa had one dust layer about 16” below surface
Grizzly had mild dust about 29” below the surface
Hoosier Pass had mild dust about 15” below the surface
McClure Pass had dust 2-3” below the surface
Rabbit Ears had one layer 42” below the surface (perhaps a consolidated layer from earlier in the season that wasn’t visible before) and another very mild 11” below the surface
Willow Creek no dust observed
May CODOS Summary
Wolf Creek was melted out
Spring Creek was melted out
Park Cone was melted out
Grand Mesa had a dusty surface
McClure was melted out
Hoosier Pass had dust layers merged at the surface, pretty mild
Berthoud Pass had mild dust layer below the storm slab at 14” depth
Loveland Pass had dust under new snow at 10” below surface
Willow Creek had patchy snow, none at our site
Rabbit Ears had mild dust mid-pack
Above: Total dust-on-snow events by month. March begins the more intensive part of dust-on-snow season. In WY2025, we saw dust events occur on January 25-26th, March 18, and April 1.
Above: Total dust-on-snow events by year. Two dust events in 2024/2025 were “wet” events and none were “dry” events. Wet means the dust came in with precipitation. Dry means it arrived without precipitation.
Below: Snow season albedo since 2006. Albedo can vary greatly depending on dust severity and precipitation events. WY2025 (red line) was “lower-end-of-average” for dust severity conditions at Senator Beck. Precipitation events, however light, were rather frequent in spring which helped keep fresh snow (as well as cloud cover) on the surface and minimized dust radiative forcing.
RUNOFF BEHAVIOR
Snowpack and dust-on-snow conditions set the stage for streamflow come springtime, and weather conditions dictate how it unfolds. As has been the case for the last several years now, a big question was just how much a hot and dry April would advance ablation of the snowpack. That month played out with slightly above normal temperatures on average and very dry conditions throughout the state (only two storms at SBB). Lower severity dust-on-snow conditions kept the snowpack in place longer than expected, nonetheless, streamflows saw a solid uptick until mid-month when a modest storm came through and provided an albedo reset and brief cooler temps. A mild storm held things in check the first of May then melt really kicked in with rates of >1”/day. Another mid-month May storm tapped the brakes and dropped streamflows below median. Being mid-May, the snowpack is poised to melt quickly, the well timed storms (albedo resets) and minimum dust conditions already resulted in the snow sticking around longer than expected and streamflows from peaking very early. Nice weather settled in and streamflows ramped up and peaking right around June 3. Many gauges saw a slightly higher peak and/or extended peak due to a rain dominate storm June 4-5. For these reasons the streamflow peak constituted melt out of snow ~11,000’ and below. The higher elevations, still retaining a healthy snowpack in some locations, still had some melting to do. With our Senator Beck weather station being the only one of a small handful of stations above treeline, we knew there was a near normal snowpack up there. The first half of June was wonderfully wet which slowed melt a tad at elevations above treeline. Some higher elevation stream gauges (like SBB) showed sideways movement during this time, but the majority started tapering off. Within a day of snow being gone at the Senator Beck site we saw the high elevation induced peak in our SBB stream gauge, pretty much the same peak Q (9.4 cfs) as when 11,000’ peak occurred. After this, streamflows started receding.
In general, the way snowmelt played out many gauges saw peak timing within a week of median and peak discharge was typically less, or very close, to the median. It is nice the peaks arrived near the normal timeframe, but what is really important is total volume, of course. Since we saw a north/south split in percent normal snowpack conditions, with northern basins faring much better than the southern, it was expected we would also see this split for streamflow volume as well. The northern mountains typically were much closer to normal estimated streamflow volumes than the southern mountains.
Above: It was a multi-peak season as recorded by many stream gauges. A skimpy snowpack towards the south kicked into the melt phase rapidly due to a dry and sunny April. Timely albedo resets in May and a wet start to June dampened snowmelt rates due to hampered incoming solar radiation, prolonged the melt of a meager snowpack until closer to the normal melt-out timeframe.
Above: We installed a snow scale last summer as well as a new snow depth sensor at Swamp Angel. The above graph compares snow depth, SWE, and precipitation at Swamp Angel and Red Mt Pass SNOTEL station, which are 1 mile from each other the way the crow flies. Swamp Angel is in a modest clearing and Red Mt SNOTEL is in a treed area. Snow depth at Senator Beck station is also shown. Data compares really well except for SWE comparisons between the SNOTEL snow pillow and the Swamp Angel snow scale near the peak of accumulation season.
Our stream gauge at the pour point of our Senator Beck Study Basin experienced essentially two equal peaks of 9.4 cfs. The first peak was May 30, reflecting the ~11,000’ elevation zone and below melt out, and June 13 reflecting the bulk of melt out at the higher elevations, 12,000’ and above.
Above: Correlation of snow-all-gone at SASP and peak Q at the adjacent stream gauge. All the severe dust years in red show SAG and peak discharge before June 1. Low dust years are shown in blue and average in green. The two years in green at lower left make sense as this was 2012 and 2018, two notorious low snow years (and dust severity was “upper-end-of average” for 2018). This year, snow-all-gone and the first streamflow peak was within a day of each other. Check out the recently published research article on this subject matter here: Twin-Peaks Streamflow Timing - Can We Use Forest and Alpine Snow Melt-Out Response to Estimate?
Below: There is a little less correlation of the second streamflow peak Q with SAG at Senator Beck Study Plot (12,200’) but still very informative when assessing possible peak flow scenarios. This year, snow-all-gone and the second streamflow peak was within a day of each other.
Above: Peaks occurred approximately May 30, June 13. At the Swamp Angel gauge it was nearly identical at 9.4 cfs.
Looking Ahead
In mid-July, much of Colorado was experiencing extreme drought conditions. A series of major fires were sparked towards the end of June, and conditions were primed for the spread of these fires. In southern and southwestern Colorado, we had our eyes on the Aspen Acres, Gold Mountain, and Ferris fires.
To great relief, a big area of high pressure settled in over to the southeast of the state of Colorado, and the dew point temps in Arizona rose: these things indicate the official arrival of the summer monsoon (cite?). The monsoon storms brought challenges to firefighting, as they usually included increased lightning activity, flash flood danger, and high winds without the promise of significant wetting. The southwest flow has brought significant if choosy rain to southwestern Colorado. We were grateful for the change, and we hope it continues. In southwestern Colorado, the monsoon is usually over by August, but there’s a chance it lingers until October (Colorado Climate Center).
In more climate teleconnection news, El Niño conditions are strengthening, with large areas in the Pacific Ocean with above average sea surface temperature. There’s 81% chance of a very strong (super!) El Niño during October-December and a 97% chance that El Niño conditions will continue through early spring 2027. Currently, the Madden-Julian Oscillation (MJO) is moving into Phase 8 (as of July 20th), constructively impacting El Niño conditions, making precipitation chances more favorable as well (cite?).
There’s hope that this super El Niño bails us out of our water worries. However, correlations between snowfall and El Niño are rather tricky. It appears to boost the odds for southwestern Colorado high snowfall events in the spring (and early winter?), in general due to a more favorable flow of moisture and warmer temperatures, but it is in no way a guarantee. Warmer winter temperatures can also be problematic, as we saw this previous year. High snowfall odds seem to be even more of a coin flip for the rest of Colorado. We love to hope though.
Unfortunately, any water surplus we may stash away at the end of a historic snow year is likely only buying a couple-year buffer. In a recent paper by CU titled “Update: Colorado River Basin Storage Continues Slide”, Lake Powell, which catches the Upper Colorado river basin outflows, historical data shows that since 1999 when the reservoir was full, periodic wet years haven’t made gains against a combination of very dry years, average years and over-allocation (Castle et al., 2026). The ‘wet’ scenario in which next year’s runoff matches WY 2023 results in an amount of water that would yield just two more years of the current imbalanced supply and demand operations before returning to (literal?) rock-bottom.
The overall trend of the climate is hotter and drier, and water demands are increasing, even if we book a good rebound year. In the meantime, we will enjoy the cooler, rainy weather that we are experiencing this summer.
UPDATE: Colorado River Basin Storage Continues Slide Toward System Crash
June 1, 2026
Anne Castle,1 Jack Schmidt,2Eric Kuhn,3 Kathryn Sorensen,4Katherine Tara5.
https://www.colorado.edu/center/gwc/media/818
Colorado Climate Center. https://climate.colostate.edu/co_nam.html
El Nino powerpoint: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
Monsoon can last as late as October:
https://www.weather.gov/gjt/monsoon
El Nino a historical perspective: https://www.ncei.noaa.gov/access/monitoring/dyk/el-nino
MJO powerpoint: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf
Historical effects of El Nino: https://sciencepolicy.colorado.edu/admin/publication_files/2001.24.pdf
