Why Is So Cold? State Climatologist Russ Schumacher Explains

Freezing-cold temperatures blanketed much of the United States last week, including Fort Collins and the Front Range of Colorado. The National Weather Service issued a wind chill watch for the northeast and north central Colorado from Wednesday evening through Friday morning, with wind chill temperatures possibly hitting 55 degrees below zero in some parts of the state.

Russ Schumacher, Colorado state climatologist and professor in the Department of Atmospheric Science at Colorado State University answered a few questions to put this holiday freeze into context.

What meteorological or climatological factors are causing the unusually cold temperatures in Colorado and beyond?

Schumacher: A very strong weather system is developing across North America, with extremely high pressure across the western U.S. that is going to plunge southward on Wednesday, bringing cold and windy conditions through the Great Plains and Midwest. Then, a strong winter storm will develop across the Great Lakes on Thursday and Friday, with a broad swath of blizzard conditions in that area.

Here in Colorado, we’re going to see a very strong cold front that will drop the temperatures from the 40s on Wednesday afternoon to well below zero by Thursday morning.

There’s cold, and then there’s wind chill, right?

Schumacher: There will be some snow with the cold front, but the real hazard will be the combination of cold and wind, with very dangerous wind chills across eastern Colorado. Extremely low wind chills can cause frostbite to exposed skin in a matter of minutes, and it is also dangerous for pets and livestock to be outside in these conditions.

Typically when we get our coldest temperatures, it’s under relatively calm conditions, and likewise when it’s windy it tends not to get well below zero. But in this event, there will be both cold and wind, so the wind chills will be nearing record lows across eastern Colorado. For example, Limon has never recorded a wind chill of minus 50 degrees in 50 years of records, and the National Weather Service forecast is for minus 54 degrees.

How unusual is this level of cold for this time of year?

Schumacher: We have not seen this level of cold in December in quite some time. The last time it was colder than minus 15 degrees in December was on New Year’s Eve in 2014.

In terms of the temperature, this upcoming weather will not match some of the historic cold snaps we’ve had in Colorado. For example, here in Fort Collins in December 1983, it went four straight days without the temperature going above zero. Other major December cold snaps occurred in 1989 and 1990.

It’s possible that Thursday will be the coldest December day since the 1990 cold snap, with the highs staying below zero in some places.

The year 1990 is when many of the record lows for December were set along the Front Range: Denver’s December record low is minus 25 degrees on Dec. 22, 1990, and Fort Collins reached minus 24 degrees that same day. The Fort Collins record for December is minus 35 degrees on Dec. 9, 1919. Based on the current forecasts, it’s not too likely that any of these records will be broken.

When can we expect this cold snap to end?

Schumacher: The good news is that the cold isn’t going to stay around for long. It will have warmed back up by Saturday, with highs back to above-average for Sunday and much of next week.