Summary

• Snow starts Tuesday night
• Continues through Thursday morning
• Most mountains will see 6-10 inches, more in the southwest
• Another quick shot of snow on Friday for the north
• Next storm around Tuesday November 11th
  

 

Sponsor

Since 1949 Warren Miller has kicked off winter and this year, launch your ski and snowboard season with the 66th annual film, Chasing Shadows, screening along the Front Range November 11 through 26.

 

Details

The storm to our west has produced quite a bit of snow from Monday morning through Tuesday morning. The snow stake at Heavenly (in the Tahoe area of California) measured about 15 inches, and the map below shows a wider view of the snowfall over the last day (multiply by about 10 to convert from liquid water to snow totals).

Source: Dr. Andrew Slater

 

As it stands now, the storm is splitting apart to our west. One split is rotating over northeastern Nevada as of Tuesday morning, which you can see on the water vapor satellite image below. The other energy that is splitting off will stay over southern California and become reinforced over the next 24 hours. You can’t really see this on the image below, but all weather models are picking up on it. This southern energy will be mostly responsible for our snowfall during the next few days.

Source: Weathertap.com

 

Today, Tuesday, will be one more warm day ahead of the storm. Temperatures are running 10-20 degrees above average across Colorado, and it’ll be warm and dry enough over the eastern half of the state that there is a Red Flag Warning (meaning that conditions are favorable for wild fires if something ignites).

Source: The Weather Channel

 

The storm will inch closer to Colorado during the day on Tuesday, and will push an initial wave of snow over the western and southern mountains on Tuesday night. This band of snow should progress across all mountains by Wednesday morning, though snow levels will start high, around 9,000-10,000 feet, due to the warm air ahead of the storm.

During the day on Wednesday and through Wednesday night, additional bands of snow will push through the mountains of Colorado, and temperatures will cool quite a bit. By Wednesday night and Thursday morning, the snow level should drop all the way down to the bottom of most valleys, around 6,000 feet.

Part of the challenge in forecasting snow amounts from this storm is weighing the combination of the wind direction and the energy (or dynamics) of the storm.

Wind direction is an important consideration when forecasting snow amounts as certain wind directions interact with each mountain range to produce more or less snow (based on the wind being forced to ascend or descend a mountain range).

The wind direction during Tuesday night, Wednesday, and Wednesday night will be from the southwest. This direction favors Wolf Creek, Purgatory, Silverton, areas west of Crested Butte and Aspen (Marble, Irwin), Snowmass (somewhat), parts of the Grand Mesa, and the Flattops. Even though Telluride is in southwestern Colorado, it is favored more by a west or northwest wind, and not southwest.

While the wind direction is a key determining factor when considering snowfall amounts, the dynamics of a storm can overwhelm a bad wind direction. This means that if the storm’s energy creates a band of very heavy snow, while there is a southwest wind, this band of snow can drop deep snow accumulations on mountains that aren’t favored by a southwest wind, simply because the snow band is strong and overwhelms the negative terrain effects.

Wrapping all of this together, a southwest wind for the majority of the storm points to the deepest snow falling in the southern and western mountains that I listed above, with accumulations around 12-18 inches. Other mountains not favored by a southwest wind are more likely to receive 4-8 inches of snow through Thursday morning.

The important caveat is that, if a band of heavy snow moves over mountains that aren’t favored by a southwest wind, it can still drop lots of snow and accumulations can be higher than forecast.

By Thursday morning, the storm will push east of Colorado and this will switch the wind direction to blow from the west and northwest. This direction favors the central and northern mountains, roughly from Aspen north to I-70 and Steamboat. Look for a few more inches during snow showers on Thursday.

We should see a brief break in the snow on Thursday night, then a quick-moving storm will bring another few inches of snow to the mountains along and north of I-70 on Friday.

Here is a map of our total snow forecast from Tuesday night through Friday, which you can find on the Powder Finder. Amounts are somewhat equalized from south to north as the first part of the storm will drop more snow on southern Colorado while snowfall from Thursday morning through Friday will favor the north. I do think some parts of the San Juans will see over 20 inches, which is more than shown here.

Source: OpenSnow.com Powder Finder

 

Saturday and Sunday should be dry for most areas, but clouds and a few snow showers could hang on over the southern mountains (San Juans and Sangre de Cristos).

Our next storm should arrive around Tuesday November 10th and will likely have temperatures even colder than this week’s storm, though snow accumulations might be lower due to less available moisture.

If you’re searching for powder, Wednesday and Thursday should be the freshest days, with plenty of leftovers on Friday. If you’re heading into the backcountry, remember that if there is enough snow to ride, there is enough snow to slide, so please be avalanche aware and head over to CAIC for the avalanche forecast.

JOEL GRATZ