JACKSON, Wyo. — Jackson Hole will end 2020 on a quiet note following a big storm the day after Christmas, but an active and snowy pattern looms ahead as we begin 2021. In this week’s article, we’ll take a look briefly at what’s ahead for the New Year, while also recapping the year 2020.
Weather Outlook through early January
The early part of this week (December 28-30) will be cold and dry with highs in the teens and lows falling below zero. The cold temperatures will extend to all elevations, which will keep the snow conditions nice and soft on the slopes.
A weak system will arrive just before the end of the year with snow showers developing late Wednesday night and continuing through the day on Thursday. Snow amounts are expected to be light and conditions should start to clear out during the evening hours on New Year’s Eve.
After a dry and sunny start to 2021 on New Year’s Day, an active pattern is likely to develop during the first 7-10 days of January as a deep trough of low pressure becomes established over the Pacific Northwest – a pattern conducive to stronger and more frequent storms. Great news for skiers!
The pattern shift will start to occur over the weekend with a leading-edge weaker storm expected on Saturday (January 2) followed by a stronger storm on Sunday (January 3). Additional storms with frequent shots of snow should be anticipated through at least the first half of next week as well.
2020 Weather Recap – Temperatures
There were some variations in temperature departures across weather stations in the valley, but the general consensus is that temperatures will end up being slightly cooler than average for the year 2020.
The coldest month of the year (at all valley stations) was in February when the average high and low temperatures at the Jackson Hole Airport were 30º and 0º respectively. The warmest month of the year was August when the average high and low temperatures were 83º and 42º respectively.
At the Jackson Hole Airport, the hottest temperature of the year was 92º, which occurred on August 17, and the coldest temperature of the year was -25º, which occurred on February 20.
2020 Weather Recap – Precipitation
The year 2020 has been slightly wetter than average across most of Teton County. The first half of the year was much wetter than the second half with above-average precipitation occurring in five of the first six months of the year (only May was drier than average). Precipitation was then well below average during the summer months, and generally close to average during the fall.
The Town of Jackson weather station was the lone outlier where precipitation has been slightly below average this year, but stations farther north in the valley and higher up in the Tetons have received above-average precipitation.
2020 Weather Recap – Snow
Snowfall and snowpack are generally evaluated for the fall to spring period rather than the calendar year. For the 2019-2020 winter, snowfall was above average at all elevations. Mountain snowpack was 123% of average on April 1, meaning it was an outstanding winter for skiers and for water supply.
Total snowfall amounts from October 1, 2019 through May 31, 2020 included 592 inches at Jackson Hole Mountain Resort (Rendezvous Bowl Plot) and 113.4 inches in the Town of Jackson.
Most Notable Weather Events of 2020
Snowiest January on Record at JHMR’s Rendezvous Bowl
The Rendezvous Bowl Plot at Jackson Hole Mountain Resort experienced its snowiest January on record in 2020 with an impressive total of 173 inches of snow falling at the Rendezvous Bowl Plot. This was also the third snowiest month ever recorded dating back to 1974, behind only December 1996 and February 2019.
The March 14-16 “Covid Snowstorm”
The Tetons are accustomed to receiving storms that result in double-digit snowfall totals, but it doesn’t happen in the Town of Jackson that often. However, during the weekend of March 14-16, just as the COVID-19 pandemic was beginning and the nation was going into lockdown, a massive storm deposited 18 inches of snow in the Town of Jackson in less than 48 hours.
Jackson received 12 inches of snow during a 24 hour period on March 15, and this set a daily snowfall record and was also the second latest date in the year that Jackson had ever received a foot or more of snow in one day. Southerly winds occurred with this storm, and this is a key ingredient to big dumps in town as moisture arriving from the south is not interfered with by the Tetons.
Jackson Hole Mountain Resort received 31 inches of snow from this storm but unfortunately closed for the year early on March 15 due to the pandemic.
Extremely Dry July and August
During the last few days of June, Jackson Hole experienced an impressive rain event and even some high elevation snow. Unfortunately, a two-month dry spell took hold after this event. While July and August are typically the driest months of the year, they were exceptionally dry this year.
The Town of Jackson only received 0.76 inches of rain total in July and August (average is 2.66 inches) and totals were not much different elsewhere in Teton County. Fortunately, July was a bit cooler than average which helped to delay fire season.
However, August was hotter than average with 90-degree temperatures recorded at the Jackson Hole Airport on three different occasions. Fire danger was very high and the precursors were set for a bad late summer fire season. We were lucky and only experienced a handful of small fires in the surrounding forests, but we did see plenty of smoke from fires in other states.
As for thunderstorms, a common summertime occurrence in normal years, this past summer was one of the least active in recent memory.
Labor Day Storm
Labor Day weekend started off with near-record heat and highs near 90 in the Jackson Hole Valley. Then the bottom dropped out on Labor Day Monday as an unusually strong and cold storm system arrived.
Jackson Hole experienced a high in the mid 70s during the late afternoon of Labor Day Monday. In the next four hours to follow, Teton County experienced a 40+ degree temperatures drop with heavy rain and frequent lightning followed by a change-over to snow. The Jackson Hole Valley experienced a rare early September accumulating snowfall, even in town.
Most notably, a massive wind event occurred in surrounding mountain ranges, especially in the Wind River Range where hurricane force winds resulted in a widespread blowdown with many downed trees. The Tetons and areas closer to Jackson experienced downed trees and limbs as well.
Coldest October Temperature on Record
Most of October was a mild month with warmer than average temperatures through the first three weeks of the month. By most accounts, we had a good Indian summer this year. However, an exceptionally strong early-season cold front arrived in late October, and Jackson broke its all-time record low for the month of October when the temperature plummeted to -9º.
Amazingly enough, this was the second year in a row that Jackson broke its all-time record low for October. And it was an anomaly in an otherwise mild stretch of weather that lasted from roughly mid-September through early November.
