CODOS Update APRIL 24, 2026: Storm Report analysis
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Below: Photos of Senator Beck Basin on March 29, April 8, and April 22. After a couple mild storms we are back where were at the for high elevation snow covered area in our Basin. Station data shows the same, see snow depth and SWE plots below.
Below: snowpack temperatures near surface has cooled a bit with a return to colder conditions particularly in the evening.
Questions About Storms and Precipitation Patterns
We have a unique dataset at CSAS that characterizes winter storms. Here are the first in a series of visualizations of this data.
First, what makes a storm? CSAS defines a winter storm as receiving 12 mm (0.47”) of precipitation with no break in precipitation greater than 12 hours. You can see a past log of our storm reports throughout the years here, and current season winter storms here. We record a number of data about these storms including: storm water content (precipitation), mean and max precipitation intensity (mm/hr), accumulated snow depth, average wind direction and speed, and peak gust speed.
Thinking about this year’s dearth of precipitation and subsequent record-low snow water equivalent, we had a few questions to ask of our data, which goes back to Water Year 2004. Specifically, are there any visual trends in the data on storm precipitation and frequency? Are there any visual trends or correlations between prevailing wind patterns, peak gust averages, and dust on snow events?
· Amount of precipitation
· Frequency of storms
· Direction of prevailing winds during storms
· Speed of prevailing winds
· Intensity of storms
· Duration of storms
· Temperature of storms
· Specific dust event analysis
Below: Number of winter storms per year, average amount of precipitation per storm, and total storm precipitation of all winter storms for the water year are plotted below on stacked bar graphs. There are multiple water years where both low storm count and low average precipitation resulted in below average season, such as WY 2012, WY 2013, and WY 2018. Conversely, high storm count and high average precipitation resulted in above average snowpack years, like in WY 2008, WY 2011, WY 2019 and WY 2023. In a few instances, low winter storm count was made up for by above average storm precipitation: WY 2005, WY 2015. In no instances did high winter storm count make up for low average storm precipitation.
Below: The prevailing wind direction of storms for the water year and peak gusts were evaluated in the below plots, overlayed with the dust events throughout our period of record. The first graph plots dominant storm directions, so, the percent storm hours axis shows the most frequently occurring cardinal direction and the percent of storm hours that occurred in that direction –higher percentages mean there was a more consistent wind pattern throughout the year. The peak gusts plot below the dominant storm direction plot shows average peak gusts that occurred during storms for that water year. There is slightly negative trend line displayed, though it is not significant (p = 0.74). No consistent pattern emerges from these plots. The biggest takeaway might be the change in dust events pre and post 2014, the variance of which is not explained by either average storm direction or average wind speed. An analysis of each specific dust event and storm would likely be more informative and could be part of a future CSAS update. The final plot is an all-storms per water year wind rose, further displaying wind directions and speeds during winter storms.
