Out Like a Lamb

Posted Thursday, March 29th, 2018 by Lucas Bohne

If you recall one of our forecasts from earlier in the month of March, I wrote about March was appearing to come “In Like a Lion”. In that post, I longed for a boost to our snowpack and the continuation of storms through the month. However, we are definitely going to end March like a lamb.

Fortunately, March was both helpful and devastating to our snowpack. The first several days of March were plentiful with snow –  with about 30″ falling in the upper Cottonwoods and about half that amount elsewhere. Another cold storm system for St. Patrick’s Day weekend was beneficial too, depositing another 1.5-3′ of snow into our Wasatch Mountains. But just a few days later, an extremely warm period brought rain to even high elevations in the Cottonwoods. This resulted in our scarce low-elevation snowpack to melt and lose some of its snow water, while upper elevation snowpacks were able to soak up that rain and hold it in the snowpack to increase our SWE.

One example of a low elevation site that experienced rain and melt is Ben Lomond Trail (elevation: 5972 ft), as shown by the following SNOTEL water year graph. The rainy events are easy to notice when precipitation accumulation (black line) increases, but SWE (blue line) decreases for a storm period- look especially at the latter half of March.

Ben Lomond Trail SNOTEL water year chart as of March 29, 2018.
Ben Lomond Trail SNOTEL water year chart as of March 29, 2018.

So overall, high elevations did decently well during March (Alta has reported 93.5 inches of snow on the month comprising 8.79 inches of liquid water). In comparison, the average March snowfall at Alta is ~100 inches, or 7.82 inches of water. Unfortunately, we still are’t sitting super pretty on the season and there is not much to look forward to in the next few days. (Data from https://www.alta.com/conditions/weather-observations/snowfall-history).

Looking back to the sad time of two months ago and comparing it to now, we can notice some improvement based on SNOTEL stations. (https://www.wcc.nrcs.usda.gov/webmap/).

January 29, 2018 SNOTEL snow water equivalent as percentage of median
January 29, 2018 SNOTEL snow water equivalent as percentage of median
March 29, 2018 SNOTEL snow water equivalent as percent of median
March 29, 2018 SNOTEL snow water equivalent as percentage of median

In these images, white circles represent near normal, greens and blues represent above normal and well above normal, and oranges and reds represent below normal and well below normal. Some areas have made quite the comeback in the last couple months, but overall this year’s above normal snowpack in the northern Rockies has persisted.

As for the next few days and into the Easter weekend, not much exciting weather is in store besides warm and dry conditions. We are expected to run 5-10+ degrees F above average for this time of year, and no major storm systems are aimed at our area in the coming days. Perhaps a skiff of snow is possible into Sunday, but don’t expect anything much more than that.

Have your sunscreen and warm weather gear ready for this holiday weekend and enjoy the spring conditions!

-Lucas

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