JACKSON, Wyo. — Following a drought-free run that lasted for about four and a half years, Teton County is officially in a drought for the first time since October 2016.
Abnormally dry conditions in March and April along with a below-average spring snowpack are largely responsible for the current drought conditions.
The U.S. Drought Monitor first classified a large portion of Teton County as being under a “Moderate Drought” on its weekly report on April 13. As of the most recent report on April 27, “Severe Drought” now covers most of the county. This is a Level 2 out of 4 drought classification, with Extreme (Level 3) and Exceptional (Level 4) being the next highest classifications.
It might seem hard to believe conditions have dried out so quickly after the second snowiest February on record in the Tetons. However, the pattern abruptly flipped around March 1 and Jackson Hole has been stuck in a cool but dry northerly flow since then with the main source of Pacific moisture blocked off due to persistent high pressure off of the Pacific Coast.
Temperatures were actually colder than average in March and April, but significant storm systems were lacking. Instead, we saw a lot of cool and cloudy days with only light snow showers or flurries.
March-April Teton Snowfall and Snowpack Update
The Rendezvous Bowl Plot at Jackson Hole Mountain just experienced its sixth driest March on record (in terms of snowfall) dating back to 1975 with only 30 inches of snow recorded, compared to a monthly average of 66 inches.
April was not any better. Although snowfall records for the month of April only date back to 2007, this past April was the least snowy on record during the previous 15 years at the Rendezvous Bowl Plot with only 17 inches recorded. Average snowfall during April is 62 inches.
As of May 1, the snow depth at the Rendezvous Bowl Plot was 75 inches, compared to an average of 105 inches (i.e. 71% of average). Snow records as late as May 1 only date back to 2007, but during this 15-year time period, snow depth on May 1 was the third-lowest, behind only 2007 and 2015.
March-April Precipitation in the Jackson Hole Valley
During March and April, the town of Jackson only recorded 0.49 inches of precipitation, compared to an average of 2.79 inches, or about 18% of average. Yikes.
The Moran weather station near Jackson Lake recorded 1.06 inches of precipitation in March and April, which was only 24% of average (the average March-April precipitation is 4.50 inches).
The image below shows the percent of average precipitation across Wyoming during the previous 60 days (ending May 3). Western Wyoming was well below average, while areas along the eastern slopes of the Continental Divide did much better. However, these areas were already in a drought prior and have only seen minor improvement.
The other concern about the lack of springtime moisture is fire danger this summer. The dry spring is looking eerily similar to 2016 (a bad fire year) when healthy winter snowfall gave way to a faster-than-normal melt-out and drier than normal spring conditions. Granted, spring temperatures were warmer in 2016 than in 2021 – at least so far.
Even so, the National Interagency Fire Center’s most recent seasonal outlook has placed Northwest Wyoming under a higher than normal wildfire risk starting in August.
So far, the outlook for the month of May based on medium-term to multi-week weather models indicates temperatures and precipitation are not expected to deviate significantly from average. However, long-range seasonal models (which granted are less accurate the farther out in time you go), are projecting warmer and drier than average conditions heading into early summer.
Alan Smith, Meteorologist
