Did you know that Denver officially reported a half inch of snowfall way back on Saturday, October 6th before sunrise? Boulder’s first snow occurred four days later on October 10th. Yes, for the first time ever, Denver International Airport beat Boulder to the punch for the season’s first snowfall. We discuss how this happened and announce the winners of the 2018 First Snow Contest.
Denver’s first snow (October 6th)
Excuse us for asking you to remember the weather from eleven days ago on Friday, October 5th! However, that was our most recent warm autumn day, or at least it started out that way. A cold front pushed through during the afternoon, dropping temperatures from the 70’s into the 40’s rather quickly. Rain showers spread over the Metro area through the evening and overnight hours.
Weather observations from BoulderCAST Station last Friday (Oct 5) through Saturday morning (Oct 6)
This particular day was a bust on several accounts by the weather models. It began with being nearly 10 degrees off on the daytime high temperature. 70’s were definitely not expected! Later on, the models overdid the amount of low-level moisture behind the front. It looked as though Friday evening and night would have widespread light rain showers across the Metro area. In retrospect, showers were fairly isolated and we were lucky to even pick up 0.25″ at BoulderCAST Station. Finally, a single heavy band of precipitation formed (see below) and led to significant dynamic cooling of the atmospheric column. This cooler air column allowed snow to briefly make it to the ground before melting across eastern Denver, despite temperatures in the mid to upper 30’s.
Radar still image from early Saturday morning (Oct 6 2018) of the rain/snow band across east Denver.
This wet snow band produced the first accumulation of the season for some folks, including Denver International Airport. The official snow total was 0.5″ in Denver. Other areas in the eastern Metro area, such as Aurora, and in the Foothills reported accumulating snowfall, too.
Snowfall reports from Saturday morning (Oct 6)
As quickly as the snow fell, it melted, with little if any sign it had ever existed by sunrise. Without social media (or the pesky news), we probably wouldn’t have known it even snowed. Did you? This time of year, anything can happen in eastern Colorado!
Boulder’s First Snow (October 10th)
Boulder’s first snow came four days later on the morning of October 10th in a similarly sneaky scenario. There was no real weather disturbance on this day. Instead, the forcing for Boulder’s first snow this season was from a passing jet streak, and a weak one to boot. Given the near-perfect orientation and position of this jet streak, we expected a few isolated banded rain/snow showers to break out across the Front Range. Before sunrise on Wednesday October 10th, one of these spotty bands passed over Boulder producing a quick 0.9″ of snow in the city. Additional snow bands paraded over through the day in the northwest Metro area, but with warmer temperatures by then, little to no accumulation was reported. This was the first visible taste of snow for most of us though, with big juicy flakes falling sporadically from Boulder to Broomfield to downtown Denver.
Snow in Denver before Boulder?
Does it seem rare that Denver recorded snow before Boulder this year? In fact, this occurrence is a FIRST! Since DIA was opened in 1995, Denver has never definitively reported snow earlier than Boulder. In those 24 years, Denver and Boulder reported their first snow on the very same day 14 times. Boulder had the upper-hand 9 of those years. Check out the table of first snow dates below.
Since Denver climate records follow Mountain Time and Boulder Universal Time, if snow begins in the evening after 5:00 or 6:00 PM MT, Denver reports the same snow one day earlier. After reviewing the hourly data from DIA, we determined this happened four times since 1995 for the first snow of the each season. DIA has never actually had snow earlier.
Table showing the date of first snow in Denver (DIA) and Boulder since 1995. Gray years were the same day (within UTC buffer), while green indicates the cities saw their first snow on different dates.
If the first snow isn’t coincidental, Boulder usually has a few days to a few weeks head-start. In the case of 2014, the separation was a full 2 months! It snowed on September 12th in Boulder, but took until November 11th for Denver to see any snow that year.
BoulderCAST 2018 First Snow Contest Results
There were more than 120 entries into the contest this year. Here are some facts about the predictions:
- Dates guessed ranged from September 29 to November 19
- Amounts predicted ranged from 0.1″ to 9.5″
- The median date forecasted was October 20, which is also the exact climatological median date
- Shockingly, the winner guessed the exact date AND amount correctly. That’s not fair!
- Two other folks guessed the exact date correctly, but were off by 0.1″ on the amount
The verification of Boulder’s first snow was October 10 and 0.9″.
Congratulations to the winners detailed below. Prizes will be disseminated via email in the coming days.
- 1st place: 12-month Premium subscription + BoulderCAST T-shirt
- Percy
- 2nd place: 6-month Premium subscription
- Mason M
- Chris V
- Katie M
- Todd B
- Anyone who guesses within 1 day OR 0.1″ correct: 2-month Premium subscription
- Denny C
- Leonard J
- Carla B
- Todd H
- Mack H
- Gillian
- Jared C
- John H
- Neil C
- Kelly P
- Jose P
- Jean C
- Myra S
- Tina
- Eva
- Tom G
- Toni C
- Archie
- Amanda F
- Tammy B
- Roger M
- Mica
- All other entries: Virtual “pat on the back”
- 96 other people
To view a complete spreadsheet of all the entries, go HERE.
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