Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Visiting our Senator Beck study sites on Friday and Monday showed we are about in the same condition as our last report. Mild dust is at the surface and below treeline there is another light dust layer about mid-pack. Dust severity has remained mild this spring which has been a surprise. Over the weekend southern Colorado was hit hard with strong winds and a big dust plume kicked up in New Mexico but fortunately stayed south of the Colorado mountains as it worked it’s way east.
The warm and mostly dry April has whittled away our meager snowpack towards the south at rapid pace. The first part of April it looked like we were going to drop fast to record low levels, and some southerly basins definitely dipped their toes in the lower minimum projections, but we did receive a couple storms this April that gave a modest boost to SWE and temporarily slowed melt.
There is some activity in the forecast over the next week. Here in our neck of the woods we could see upwards of 2” precipitation. This weather will slow snowmelt and cover the surface dust. Not long after this snowy period we will be reporting on our dust-on-snow observations throughout Colorado, so stay tuned.
Below: Swamp Angel on April 28. We measured 18.9” SWE, with depth of 4.2’, and density of 371 kg/m^3. The overall dust severity has not changed over the last few weeks. A couple of light dust layers have merged at the surface and a couple light layers are still buried under the snow.
Below: Senator Beck Study Plot on April 25. Measured SWE was 22.1” with depth of 4.9’ and density of 374 kg/m^3. In the snow profile no dust layers were apparent, but dust was on the surface and concentrated in preferential collection areas across the landscape.
Satellite image of dust plume (bright magenta) making it’s way across New Mexico Sunday night (April 27). Fortunately the plume stayed south of Colorado until it was well east of the mountains.
Below: Labeled on the plot is our physical measurements from the snowpits we dig at Swamp Angel throughout the season. Included as well is a percentile map of the SNOTEL stations across Colorado. To dig in more to percentiles and snowpack trends, read the April post on Colorado Climate Center’s blog here.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
SUMMARY
Colorado has begun March with “high” conditions completely dominating the range of snowpack conditions among major basins across the Colorado Mountains. This update summarizes snowpack conditions state-wide and evaluates March 1st snow water equivalent (SWE) data from SNOTEL stations associated with our eleven CODOS sites and places them within the framework of the Dust Enhanced Runoff Classification scheme (DERC) developed by CODOS. A summary is presented by individual Basin, and provides a site-specific analyses for each CODOS site (linked below).
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
The calendar still shows on average 2 months left in the snowpack accumulation season, but walking around Silverton it feels like the latter part of spring. Driving along highway 550, adjacent slopes are riddled with wet avalanche activity. At Swamp Angel (11,060’) the snow is perfect for making snowballs. The data is a bit off the charts as well; we have never seen air temperatures this high at Swamp Angel (see below) and SNOTEL averages for the entire state are showing the same record highs.
The wee storm that passed through the San Juans about a week ago brought a little bit of snow (0.43” precip) and a little bit of dust (see picture below). On Jan 31 the dust was ~5” below the surface; now I expect with the warm-up, it is at or near surface at many locales. Given the current state of the snowpack, a dust event would be a welcome occurrence, since a dust event often means a snowstorm. The reason why dust conditions are pretty minimal for this point in the season is we haven’t received many storms in total and many of the early season storms have came down from the north.
This warm-up over these last few days (with the bit of dust near surface) has resulted in the snowpack taking a leap towards isothermal conditions. Our new vertical snow temperature sensor shows this really well (see below), where we have watched the snowpack warm to at least -5 degrees Celsius even at our higher Senator Beck station located at (12,200’). Qualitatively, snow cover is thin or non-existent in general, but particularly on southerly facing slopes and lower elevations. Over the last few days snow covered area dropped off at least 10% in most Basins as well.
In terms of the near forecast, it looks like this weekend the San Juans will get missed by a middling storm that might drop a few inches on the northern mountains of Colorado. In terms of mid-month: NOAA’s 6-10 day outlook (starting February 11th) foretells a cooling down, and some good chances for significant precipitation in the middle of the month. Some very good chances? We will see.
Our USGS colleagues have been very prolific, in addition to the recently published paper about microplastics in our snowpack, they just published another journal article titled Light Absorbing Particles Deposited to Snow Cover Across the Upper Colorado River Basin, Colorado, 2013-2016: Interannual Variations From Multiple Natural and Anthropogenic Sources. CSAS and the Colorado Dust-on-Snow Program provided the samples used in the analysis for both of these publications.
Snow School:
Still thinking about Snow School for Water Professionals? Just tell your supervisor it is the best training around. The class will be held February 19 - 21, 2025. The combination classroom and field course will begin on Wednesday morning at our office in Silverton and end on Friday afternoon (2.5 days). The class is perfect for anyone wanting to learn more about the role of snow and our mountain environments as it pertains to water resources, designed to enhance understanding of snowpack processes, snow monitoring and data. As in years past Karl Wetlaufer with NRCS will give the class a lecture and then a tour of Red Mt SNOTEL station. Click here to download flyer. You can pay with credit card at snowstudies.org. Please do not hesitate to contact me with questions.
Above: A lot of squiggly lines, but these plots are showing the temperature of the soil and snowpack at 10 cm increments. Depth below ground and height above ground are color coded. Soil temperature at 50 cm below ground to ground surface is near zero degrees C. Starting at the ground/snowpack interface (SnoT_GndC_Avg) the snowpack is near zero and as you go up the snowpack towards the surface the temperature gets colder. Looking at this past week for both plots, the snowpack has warmed rapidly so now, both at 11,060’ and 12,200’, the entire snowpack is between 0-5 degrees Celsius.
Below: Daily average air temperature for Swamp Angel. Extreme temperature swings in the past few weeks.
Something that never gets enough attention, sublimation. estimated sublimation rates have been high with the warm-up. The modeled sublimation map for 24 hours ending Feb 5 shows around 0.5 - 5 mm in one day.
Plot of SWE, snow depth, and cumulative precipitation for both Swamp Angel and nearby Red Mt SNOTEL.
Snow profile at Swamp Angel on January 31. Note the dust layer at about 6” below surface.
Bureau of Reclamation: Snow Water Supply Forecasting Program
A Center for Snow & Avalanche Studies and Colorado State University Collaboration
Demonstration and Evaluation of a Cosmic Ray Neutron Rover as an Emerging Snow Monitoring Technology for Improved Water Management
It is hard to overstate the importance the snowpack is to life on earth. We rely on water to grow food and live, and nearly 1 billion people on the planet rely on mountain snowpacks to provide the water necessary to maintain their existence and their communities. Snow is a crucial natural reservoir.
Numerous challenges are associated with measuring and monitoring the snowpack. Snow is notoriously spatially variable; where one aspect in the mountains might have depths of 1-2 meters while the neighboring aspect could be totally bare. Freshly fallen snow can have a density and water content of less than 10%, while late season snowpack can be nearly 40-50% water. Given the spatial, temporal, and financial challenges, how do we best quantify how much water is in our snowpack at a given time?
The Center for Snow and Avalanche Studies is hosting a research project in partnership with Colorado State University (CSU) to test a cosmic ray neutron sensor to measure snow water equivalent (SWE). The Center for Snow and Avalanche’s Senator Beck Study Basin is in a prime spot for snowpack studies. We sit at the headwaters of important tributaries to the Colorado River and the Rio Grande, two major river systems that supply water to communities as far as Mexico and California, irrigate croplands, and are natural ecosystems supporting diverse wildlife. We are also representative of other high alpine snow-dominated watersheds across the planet, making the monitoring we do part of a greater endeavor to understand snow processes, test new technologies, and maintain a long-term record of the natural environment.
Stationary weather stations offer invaluable data - the SNOTEL network for example is a snow monitoring network spread across the Rockies and is utilized in so many applications across the US and Canada. However, sensor, installation, maintenance and data analysis costs associated with each station are extensive.
A cosmic ray neutron rover is a non-invasive method to survey the snow. Other non-invasive methods of estimating and monitoring SWE use remote sensing, such as airborne lidar or satellite-borne sensors, to find the depth of snow. Airborne LiDAR establishes baseline ‘dry’ or ‘snow-off’ conditions, which are then used to calculate the relative difference as the snow accumulates and the season progresses. In these applications, a snow density and other modeling is needed to arrive at the water content within the snow. Cosmic ray neutron sensors have the potential to fill gaps in existing data collection methods. Stationary cosmic ray sensors are already widely used in soil moisture monitoring and agricultural applications, where farmers are trying increase the efficiency of their irrigation practices. Use of cosmic ray sensors in mobile and snow applications is still in the testing phase, with promising results so far.
What are cosmic rays, you might be wondering? Cosmic rays are actually cosmic particles travelling from space, mostly believed to originate from the sun (but also come from black holes, exploding supernovas, or colliding galaxies). Most upon hitting the earth’s atmosphere and magnetic field are stopped from entering further; however, some hit particles in the earth’s atmosphere and shatter them. A cosmic particle hitting another particle in earth’s atmosphere fractures into many secondary particles. About 90% of cosmic ray particles are hydrogen, 9% are helium, and 1% are heavier elements, like iron. When a cosmic ray particle (like a proton) impacts other particles in the earth’s atmosphere, it causes a nuclear reaction and an expulsion of particles from the particle impacted.
The collisions of cosmic ray particles and other particles in the earth’s atmosphere result in the creation of “fast”, high-energy neutrons. These neutrons travel into the soil or snow and are moderated by interacting with hydrogen in the form of H2O within the soil and snow. In the case of snow, some to most of the neutrons are blocked from returning to the atmosphere by the snowpack. Cosmic ray neutron sensors measure the moderated neutrons which have interacted and slowed due to the presence of hydrogen atoms in a radius of around 200 meters (650’). In simplified terms, the lower the neutron count, the higher the presence of water. Through processing the neutron data, we can infer the amount of hydrogen, and therefore water, in the snow or soil.
The CSU project is testing the feasibility of using a cosmic ray neutron rover (a moving sensor). This past fall, CSU and CSAS gathered soil moisture samples and took snow-free neutron counts at our study locations on Highway 550. In phase one, this winter, we will be driving Highway 550 with the cosmic ray neutron rover and taking neutron counts along the way (at a speed of 25 miles per hour, no more, no less!). We also will take stationary measurements at study sites along 550 and ground-truth the rover data with physical measurements of SWE and snow depth in a radius around the rover. Phase two, water year 2026, we will pull the rover with a snowmobile along unpaved roads to test the capabilities of determining SWE without the presence of the highway and snowbanks, while continuing to do manual measurements. Phase three, water year 2027, involves taking the rover over to the Dolores watershed. Throughout the phases of this project, our field collected data, SNOTEL, and CSAS data will also be used to evaluate the rover data.
We are really excited to be partnering with CSU on this research project! This study will be the first to extensively test a Cosmic Ray Neutron rover for SWE estimation. The data collected during this project will be applicable to current water resource issues and is a potential new tool for water resource managers and forecasters.
Potential Benefits of Cosmic Ray Neutron Rover:
Mobile: Able to collect data where and when it is most critical
Cost Effective: The cost of a rover is cheaper than installing a weather station (although the rover is not intended to replace weather stations)
Large Footprint: Provides SWE measurements over a large area (650’ radius)
Fills Spatial Gap: Fills gap between a stationary weather station (1 point), and watershed scale airborne observations (more expensive)
References:
Lerner, L. (n.d.). Cosmic Rays, explained. University of Chicago News. https://news.uchicago.edu/explainer/what-are-cosmic-rays#:~:text=Cosmic%20rays%20are%20particles%20from,and%20made%20harmless%20to%20humans
Köhli, M., M. Schrön, M. Zreda, U. Schmidt, P. Dietrich, and S. Zacharias, 2015, “Footprint Characteristics Revised for Field-Scale Soil Moisture Monitoring with Cosmic-Ray Neutrons,” Water Resources Research, 51, 5772-5790, doi:10.1002/2015WR017169.
Zreda, M., W.J. Shuttleworth, X. Zeng, C. Zweck, D. Desliets, T. Franz, and R. Rosolem, 2012, “COSMOS: the COsmic-ray Soil Moisture Observing System,” Hydrology and Earth System Science, 16, 4079-4099, doi: 10.5194/hess-16-4079-2012.
Schrön, M., S.E. Oswald, S. Zacharias, M. Kasner, P. Dietrich, and S. Attinger, 2021, “Neutrons on Rails: Transregional Monitoring of Soil Moisture and Snow Water Equivalent,” Geophysical Research Letters, 48, e2021GL093924, doi: 10.1029/2021GL093924.
It is deep winter here. We have had significantly cold mornings the past few nights with a bit of flurries; the last week we had cold, clear nights, waking to surface hoar glittering everywhere. It was quite a beautiful sight. Avalanche danger has downgraded to moderate but the snowpack feels active in our neck of the woods still. Lots of whumping and shooting cracks in flat terrain during our monthly sampling for the US Bureau of Rec/CSU Cosmic Ray Neutron rover project along US-550 last week, though things have stabilized a bit since then. The weekend flurries amounted to a few inches accumulation as 0.35” precipitation – not even considered a storm by our minimum 0.5” requirement.
Currently, Swamp Angel is slightly below the median for seasonal cumulative precipitation, at 13.4” (see plots below). After an early season jump, December flatlined until the holidays. Since then, we’ve received a few bumps of precipitation but nothing ground breaking. Red Mountain SNOTEL is sitting at 101% of median SWE for this year. Particularly the Southern Basins are falling further behind; the Upper Rio Grande Basin is at 76%, Arkansas 99%, Animas/Dolores/San Miguel/San Juan 76%, Colorado headwaters 98%, Gunnison 94%, Yampa 94%, South Platte 101%. Nothing the Southern Basins can’t come back from but the ridge is still in place over the West Coast resulting in the next opportunity for significant precipitation not until next weekend. But it will be cold, record setting cold, so bundle up!
And in the tropical Pacific Ocean, weak La Niña conditions persist, with a 60% chance of neutral conditions developing March-May. Even though it is a weak La Niña, there is still possibility of strong La Niña conditions, meaning precipitation anomalies (dry for us). See charts below.
We have December monthly summary plots posted below for Swamp Angel as well. The station has been running smoothly, and progress is being made on getting camera images up and running!
As far as dust goes, it has been pretty quiet so far this season. We have not observed any dust at Senator Beck Study Basin or elsewhere. The lack of storms also means reduced chances of dust deposition. Starting in March we will begin the statewide dust-on-snow tours.
There are still a few spots left in the Snow School, see details below.
Stay safe out there!
Another shoutout for Snow School for Water Professionals . The class will be held February 19 - 21, 2025. The combination classroom and field course will begin on Wednesday morning at our office in Silverton and end on Friday afternoon (2.5 days). The class is perfect for anyone wanting to learn more about the role of snow and our mountain environments as it pertains to water resources, designed to enhance understanding of snowpack processes, snow monitoring and data. As in years past Karl Wetlaufer with NRCS will give the class a tour of Red Mt SNOTEL station. Click here to download flyer, please circulate in your workplace and forward announcement to folks you think might be interested. You can pay with credit card at snowstudies.org. Please do not hesitate to contact me with questions
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
Dust Free So Far and Healthy Snowpack
Greetings From Silverton,
Despite a dry and lackadaisical start to winter, persistent snowcover in Senator Beck occurred on November 21, we have seen a major turn-around with a steady stream of productive storms. We have received eight winter storms so far (Storm #8 Report will follow shortly) that in and of themselves have totaled ~10.0" of water. Snow depth at Swamp Angel is at 4.5’ and the wind effected Senator Beck site is lingering around 1.5’.
After a worrisome October and November when Colorado received very little precipitation and experienced very warm temperatures, winter finally kicked into action and Colorado started receiving abundant snowfall, building the snowpack rapidly during the months of December, January, and into February. One of the big stories this winter season is the atmospheric rivers that fueled these productive storms, which were record breaking in some locations. On the other end of the spectrum, one of the other big stories this winter is the observed warmest March on record. The effects of this hot month (preceded by a very warm February) was a rapid warming of the snowpack and snowmelt at lower elevations and valleys, resulting in most stream gauges observed a 2-3 week bump in stream flow in mid-March thru the first part of April. However, Colorado recovered from the hot/dry spell with a long stretch of regular precipitation beginning around March 23 – April 4. A dry spell was again repeated April 5-19. And, starting the latter part of April regular precipitation (however sparse) was observed steadily but intermittently until June 1.
At the Center for Snow and Avalanche Studies’ (CSAS) Senator Beck Basin Study Area (SBB) at Red Mountain Pass, the primary Colorado Dust-on-Snow Program (CODOS) monitoring site, WY2017 produced a total of four separate dust-on-snow events, on the light side of a typical dust loading season based on observations going back to WY2005. Dust season began relatively late in the season. With the abundant moisture in the dust source area, the Southern Colorado Plateau, dust mobilization was kept in check until March when soils started drying out. Dust-on-snow events March 5, 23, 31 and on April 9 were documented. Surprisingly no dust events were observed the rest of April and May, although a couple haze events were noted. On June 12 a big dust storm in the desert southwest was observed with the USGS dust cameras, additional dust on any remaining snow in the Colorado Mountains was not observed at lower elevations, but it is possible some higher elevation snow cover could have received additional dust from this event. Of the four documented dust events, two of these events were pretty heavy in their severity. The end result, even though total mass loading of dust was light, with the location of the dust in the snowpack (i.e. upper portion) and its consequential role in snowmelt, we classified dust severity as “Average”, albeit the lighter side of average at SBB. Northern and some Central CODOS sample sites in Colorado were classified as “Minimum” dust severity. The transition from “Average” to “Minimum” severity took place in Central Colorado, thus some Central and all Southern CODOS sites were classified as “Average”.
