Skip to content

Breaking News

People work to dig out their cars in downtown Boulder on Nov. 26, 2019. Traveling in Boulder was difficult with the heavy snow that fell overnight and continued into midday.
People work to dig out their cars in downtown Boulder on Nov. 26, 2019. Traveling in Boulder was difficult with the heavy snow that fell overnight and continued into midday.

In the finer print of the National Weather Service webpage, the curious can always dig into the “forecast discussion” for a deep dive into what is coming and why. It is typically rendered as a dry, if highly detailed, analysis.

But a short-term forecast update posted there at 3:40 a.m.Tuesday ventured beyond the usual technical lingo such as “synoptic scale” and “vertical stacking” to note that Boulder and Larimer counties should be bracing for a second round of snow before the ongoing storm’s conclusion that could “potentially double” the prodigious amounts already stacked up on the ground.

“That’s a lot of snow!” the forecast observed, settling for terminology anyone can grasp, and making an emphatic point with which no one with or without a science degree would argue.

Snow accumulated across Boulder County Tuesday at a rate that at times reached 1 to 2 inches an hour, prompting backyard observers to break out their yardsticks and sending climate historians to the record books, concluding that it was Boulder’s biggest single November snowfall this century.

BOULDER, CO - Nov. 26, 2019: ...
RTD buses get stuck trying to climb the hill on Broadway from Arapahoe. Traveling in Boulder was difficult on Nov. 26, 2019, becuse of the heavy snow that fell overnight and continued into midday.

Colorado State Climatologist Russ Schumacher took a break in shoveling at his home on Tuesday to explain how Thanksgiving week ended up looking a lot like what people might be happier to see at Christmas.

“We have this pattern that sets up with big high pressure over the eastern Pacific and up toward Alaska that then plunges this low pressure over the Four Corners area,” said Schumacher, who is based at the Colorado Climate Center at Colorado State University in Fort Collins.

“For our big snowstorms here, that’s a pretty common pattern. The upper level jet stream is particularly strong with this storm, which I think contributed to the intensity of the lifting, for the storm to form here, and the intense snowfall. We saw a combination of the jet stream forcing and strong upslope flow. Those were the big contributors to the big, intense snow.”

He noted several prodigious snowfall amounts registered in the foothills of the northern Front Range, including 25.1 inches near Jamestown by 7:30 a.m. Tuesday. That was actually dwarfed at the same hour by 35.5 near Livermore, northwest of Fort Collins in Larimer County.

Klaus Wolter, a research scientist now retired from the University of Colorado Boulder’s Cooperative Institute of Research in Environmental Sciences, who lives near Jamestown, on Sunday afternoon issued to friends and colleagues a detailed forecast of the storm that put the coming onslaught in historical context.

“Mind you, one-foot snowstorms in November used to be common in Boulder during the 1990s (I counted four of them,)” Wolter wrote to his network, “including two within five days in 1992 that dumped 34″ of fluffy snow (not quite 2″ of moisture) …The 21st century has only recorded two of them, last year and in 2014, with less than 3/4″ of moisture each. So Boulder may end up with more snow and moisture than any November storm in more than two decades.”

And so it did.

Historically, hefty snow dumps on the northern Front Range in November have hardly been unheard of, Schumacher said. Fort Collins’ largest single 24-hour snowfall on record, he said, was the 21.1 inches that fell in that city on Nov. 20, 1979. Boulder’s second highest single-day total, he said, was the 22 inches that fell on that same date.

Boulder’s highest single-day total, Schumacher noted, was 22.1 inches, coming on Oct. 25, 1997.

Boulder meteorologist Matt Kelsch said it was important to note that the numbers offered by Schumacher were calendar-date totals, not 24-hour records. Significant 24-hour totals are often reached across two consecutive dates, he said. Boulder did, in fact, set new record for the 24-hour period starting at 5 p.m. Monday with 20.7 inches. The previous record for the date was 13 inches in 1959.

“At the current climate station we have had two really big 24-hour totals: about 26″ on Oct 24-25, 1997 (the storm total was 29.8), and 25.5” on Dec 20-21, 2006,” Kelsch wrote in an email. “There were probably even bigger ones prior to 1990, but the max 24-hour was not recorded.”

Active week for nation

The National Weather Service map for the contiguous 48 states in the U.S. on Tuesday was a crazy quilt of pinks and purples pretty much from coast to coast, signaling potential hardships for travelers across the country.

The National Weather Service map for the 48 contiguous United States as of 1 p.m. Tuesday.

Boulder meteorologist and writer Bob Henson, who blogs for Weather Underground, which is part of IBM, noted that the weather picture across much of the United States as people prepare their turkeys is “an active pattern, for sure,” with Boulder in the targets of a double-barreled storm system. The Monday-Tuesday first barrel was the most potent of the two for the Front Range.

“The second lobe of the storm will dig into the Four Corners and then pull out across Colorado late this week. Flagstaff, AZ, may get as much as 30”, which would make it one of the biggest autumn snowstorms in that city’s history,” Henson —  who saw about 2 feet of snow at his home in Boulder’s Martin Acres — wrote in an email.

“That second lobe will dump some more mountain snow in Colorado, and perhaps spin up blizzard conditions toward the Black Hills around Saturday, but the configuration is such that Denver-Boulder may only see showery light snow.”

Henson pointed out that, as most long-term observers of local patterns are aware, Boulder County’s biggest snows typically occur in the fall and the spring, “so this storm fits the pattern well.” They also usually coincide with an El Niño year — but an El Niño is not officially in place.

An El Niño is abnormal weather pattern caused by the warming of the Pacific Ocean near the equator, off the coast of South America, which can have significant winter weather impacts across much of the United States.

“However,” Henson wrote, “an eastward-surging oceanic feature called a Kelvin wave has helped put the atmosphere and ocean in a ‘El Niño-like’ pattern, with sea surface temperatures in the weak El Niño range.”

Boulder’s National Oceanic and Atmospheric Administration is not predicting that situation to persist throughout the winter. But Henson would not rule out the possibility of “a bona fide El Niño event” emerging. NOAA’s most recent forecast, he said, put the chances for an El Niño for November through February at close to 40%.

“So the bottom line is that El Niño-like conditions may have given the atmosphere over the western U.S. a boost this week,” Henson wrote.

More snow, less impact

Schumacher said round two of the week’s wintry weather should be a particularly strong snow producer for Colorado’s southern mountains, which he said have not seen the same bounty that the northern mountains have been enjoying so far this season.

For Boulder County and the rest of the northern Front Range, he said, there may be a few more inches of snow, “but nothing like this storm.”

As the Front Range digs and out resumes its Thanksgiving preparations, Schumacher acknowledged that events such as the Monday-Tuesday storm, which puts the lives of so many on pause for a day, provide an extra spark of energy to women and men in his profession.

“These are the storms that keep us all excited in what we do,” Schumacher said.

Join the Conversation

We invite you to use our commenting platform to engage in insightful conversations about issues in our community. We reserve the right at all times to remove any information or materials that are unlawful, threatening, abusive, libelous, defamatory, obscene, vulgar, pornographic, profane, indecent or otherwise objectionable to us, and to disclose any information necessary to satisfy the law, regulation, or government request. We might permanently block any user who abuses these conditions.