JACKSON, Wyo. – During the last week of October, a major winter storm produced 10-20 inches of snow in the Tetons. This storm was followed by an early-season cold snap with several days of below-average temperatures.
Heading into early November, we are undergoing another shift in the weather pattern. The cold and dry pattern from recent days will transition into a mild and wet westerly flow from the Pacific with subtropical origins. The result will be multiple moisture-laden storms with mountain snow and valley rain along with milder temperatures.
Late October Recap
A powerful early-season storm on October 25-26 produced 18-21 inches of snow at Grand Targhee and 13-20 inches at Jackson Hole Mountain Resort. This storm was followed by several days of cold temperatures, ensuring that this new snow was not going anywhere and would set the base for the upcoming winter.
The town of Jackson technically saw its first snow of the season at the tail end of this storm, but snow amounts were minimal, ranging from 0.2 to 0.4 inches around town. Snow amounts were higher in valley areas north of the airport, ranging from 1-3 inches.
This storm was followed by cold air as highs were only in the 30s in Jackson from October 26-29 with lows in the teens to single digits. The coldest temperature in Jackson during this period was 9ºF on the morning of October 30, while the top of Jackson Hole Mountain Resort got down to 0ºF on this same morning.
October – Full Month Recap
Despite the cold snap to finish the month, overall October was warmer and wetter than average with near-average snowfall depending on elevation and location.
Temperatures in the town of Jackson were 2.1 degrees above normal with an average high in October 2023 of 58.2ºF and an average low of 28.2ºF. The “normals” for October are 57.8ºF and 24.4ºF.
Precipitation was above normal in October with 2.83 inches recorded in Jackson. Wet systems early and late in the month were largely responsible for this. The October precipitation average is 1.41 inches, so we doubled this value.
This was the wettest October in Jackson since 2016. Also, this was our third month in a row with above-average rainfall, and our fourth out of the last five months with above-average rainfall (only July was below average).
Total snowfall at the Rendezvous Bowl Plot at Jackson Hole Mountain Resort was 36 inches, which is slightly above the average for the month of 30 inches. Grand Targhee received 50 inches in October, and while historical records are limited there, this was almost certainly above average.
Snow depth (the amount of snow on the ground) was 12 inches on the last day of October at the Rendezvous Bowl Plot, which is right around average.
Also, this is your yearly reminder that October snow has almost no correlation with snowfall in the winter ahead.
As of November 1, the average snow line is around 7,000 feet in the Tetons, with fluctuations depending on aspect and sun exposure. Also, there may still be some light snow on the ground in the northern valley.
Upcoming Weather Pattern for Early November
A series of moisture-laden systems involving subtropical air will slam the Pacific Northwest over the next week, and this moisture will also reach the Tetons, resulting in frequent shots of rain and snow.
This wet and relatively warm pattern is informally known as a “pineapple express” owing to the subtropical origins of moisture near Hawaii.
The first storm will reach the Tetons on Thursday and will bring rain and snow to the area from Thursday afternoon through Friday afternoon. Snow levels will rise to 7,500 to 8,500 feet as warmer air invades the area. The higher elevations will receive heavy, wet snow from this system.
Another storm will then arrive on Saturday and Sunday with similar snow levels expected initially, though snow levels could potentially dip to the valley floor by late Sunday as some models are projecting colder air to arrive. There is still substantial model disagreement on the track of this storm, which will influence snow/precipitation amounts and temperatures.
Heading into the first half of next week, additional storms are likely to arrive. Temperatures may also trend colder, which could allow for snow levels to dip to the valley floor at times with accumulations possible.
Over the course of the week, the Tetons could receive significant snow totals with snow generally being on the wetter/denser side, with a gradual trend toward lower-density snow by next week (relatively speaking).
Extended Outlook
We may see a short lull in the pattern mid to late next week, then long-range models are hinting that storms could return to the area around the weekend of November 11-12.
Note: My next weekly weather post will be on Wednesday, November 15.
Alan Smith, Meteorologist
