With 2019 coming to a close, we thought we'd take a look back at some of the most significant weather and climate stories from Denver and across Colorado over the last ten years.
The one that first came to my mind was the 2013 floods, but quickly we had a list of events much longer than we've even included here.
The last decade was marked by many warm years, catastrophic floods and fires, and plenty of variability in snow and ice from year to year. Oh, and of course plenty of beautiful, sunny Colorado days.
2012 fires and severe drought
2012 marked by drought and fire across Colorado. There were too many fires to mention here, but some of the state's largest and most destructive fires occurred in this year.
The High Park Fire started on June 9th just west of Fort Collins. The fire grew rapidly the first couple days, fueled by extremely dry tinder and high winds. The fire burned 87,284 acres and was the second-largest on record for Colorado. It also destroyed 259 homes, which at the time was the most destructive fire in state history. The cause of the fire was lightning.
The Waldo Canyon Fire was another enormous fire that year. It started a couple of miles northwest of Colorado Springs on June 23, 2012, and wasn't declared 100% contained until several weeks later. The fire destroyed 346 homes, with insurance claims totaling more than 453 million dollars.
The fires came at the height of the state's worst statewide drought of the last decade. As of early July 2012, over 70% of the state was classified as under Extreme Drought by the U.S. Drought Monitor, and 99.98% of the state classified as under Severe Drought or worse:
2013 Black Forest Fire
The Black Forest fire started on June 11, 2013 during the midst of a Red Flag Warning and scorching heatwave across Eastern Colorado.
According to El Paso County records, 48 homes were lost in the fire, which also claimed two lives. Damages totaled $420.5 million dollars, and become the most destructive fire in Colorado history for property, surpassing the Waldo Canyon Fire the year prior.
In all, an estimated 13,000 homes and 38,000 people were evacuated. It took 10 days for the fire to be contained, with over 14,000 acres being burned.
The cause of the fire was ultimately determined to be human-caused, though the the final report concluded that it was likely not arson.
2013 historic floods
Perhaps the most memorable weather event of the last decade for many was the devastating flooding in September of 2013. This event was remarkable by any measure, not the least of which was that it followed on the heels of 2012's extreme drought. As of August 2013, most of Northeast Colorado was still experiencing moderate drought conditions, by mid-September Northeast Colorado was drought-free.
That September became the wettest September on record for Colorado and the 10th wettest month on record overall. The wettest month on record was April of 1900, followed by May of 2015 (coined "miracle May") as it felt like it may have never stopped raining at the time.
This event also set a new state record for precipitation in a 24-hour period. Fort Carson reported 11.85" on September 12, 2013 (wow!!), breaking the old 24-hour record of 11.08" that fell in Holly, Colorado in 1965.
Boulder County and surrounding Front Range foothill communities received anywhere from 12 to 21" of rain in eight days. Boulder itself recorded 17.24" of precipitation, which is 85% of the city's annual average.
It wasn't just the Front Range foothills and adjacent communities that were hit hard from the flooding. Communities well east of the heaviest rainfall dealt with awful flooding in the following weeks as the South Platte roared to record levels. Weld County hit particularly hard. Hundreds of residents stranded by rising waters and farmland across Northeast Colorado saw devastating damage.
Colorado sees its fair share of tornadoes each year, with many counties across Eastern Colorado considered part of "Tornado Alley." While most tornadoes across the state are not of the "violent" variety typically found across Texas, Oklahoma, and Kansas –– the state has seen its share of strong tornadoes over the years, and plenty of picturesque ones as well.
According to records kept by the Tornado History Project, Colorado saw 314 tornadoes over the last decade –– the vast majority of which were EF0 (the weakest ranking) on the Enhanced Fujita Scale. A few, however, were stronger, including an EF3 in Boulder County in 2015, and 13 EF2 tornadoes over the years.
Here's the storm survey report from the 2015 EF3 tornado issued by the National Weather Service in Boulder:
The tornado that occurred along the Boulder and Larimer county line on Thursday, June 4th, has been rated an EF3 at its highest damage point, with maximum winds estimated at 135 to 140 mph. The path length was 6 miles long with a maximum width of 1/4 mile at times. The tornado first touched down at 6:30 PM approximately 3 miles south of Berthoud, and then tracked to the West/Northwest and lifted some time after 708 PM 6 miles southwest of Berthoud. The majority of the damage was EF1, with some areas of EF2, and a few small areas of EF3. Updated Damage Points are shown below.
With extensive damage to trees and property in its path:
One of the most stunning tornadoes to be captured in Colorado came near Simla, CO in 2015. This photo captured by James Smart is one of the most widely shared tornado photos of the last decade (certainly from Colorado), and it's clear why:
Our very own Matt Makens was chasing that storm as well. Some of you may remember these touched down during one of our Weather5280 meetups and we live-streamed Matt's coverage into the room, all feeling a hint of jealously. Here's a shot he got from one of the Simla tornadoes that touched down that afternoon:
2017 hailstorm, costliest on record
The May 8th hailstorm of 2017 dethroned the 1990 storm for the costliest hailstorm on record for Colorado. The 1990 storm tallied an estimated $1.1 billion in damages (2016 dollars), while the 2017 storm climbed to $1.4 billion after wreaking havoc across the northwestern Denver metro area.
Below is a look at the hail track from May 8th, a path of 1" diameter and greater extended from Evergreen northeast through Brighton:
For the first time since the U.S. Drought Monitor began tracking such numbers (2000), Colorado managed to become 99.99% free of any Drought Monitor classification (includes D0 Abnormally Dry). When compared to the map from 2012 above, an exceptional difference to be sure!
2019 state record high temperature
As we first reported here on Weather5280, and confirmed by the state climatologist, Colorado set a new record high in July of this year with a 115-degree reading taken at John Martin Dam near Las Animas, CO on July 19th. This broke the old record of 114-degrees set twice, once in 1933 and again in 1954.
It was the first state record to fall on the warm side since South Carolina set a new maximum temperature record in 2012.
2019 Largest hailstone on record
The state's new largest hailstone on record was found in Bethune, Colorado in August. The hailstone measured 4.83" in diameter (confirmed by both the Colorado Climate Center and NWS Goodland), breaking the old record of 4.5" (set many times over the years). It's believed the stone was even bigger at impact, as it took about 30 minutes to move to a freezer, and initial photos indicated a larger size than at the official measurement.
2019 lowest pressure on record for Colorado
In 2019 the records kept falling. This one quite literally. On March, 13, 2019 the pressure fell to 970.4 millibars in Lamar, Colorado as explosive cyclogenesis took place over the Southeast Plains.
I believe the official record is still being solidified, as there was no "official" record kept of low pressure prior to this year. That said, there's no record anywhere in the state of a minimum pressure less than 972mb, and there were multiple recordings below that number in March. The 970.4mb was the lowest we could find, but many stations near Lamar were in the 970-972 range. Lowest pressures on record were also measured at Denver International Airport (979.01 mb), Pueblo (974.2 mb) and La Junta (971.2 mb) during the storm.
State climatologist Russ Schumacher confirmed as well that the readings seen from the March "bomb cyclone" were indeed lower than any previously recorded:
Pressure continues to plummet in southeast CO as the cyclone intensifies...La Junta now down to altimeter setting of 28.81", SLP of 971.7 mb. I can't find evidence of a lower pressure (by either method) in Colorado in the past records (though we'll keep perusing the data) #cowx pic.twitter.com/XovFAH9GsQ— Russ Schumacher (@russ_schumacher) March 13, 2019
Snowpack over the decade
While we saw some great snow years in the mountains over the last decade, the bias was certainly for below-average snowpack year over year. The two big exceptions to this were 2011 and 2019, with 2011 featuring some of the best late-season snowpacks on record:
There were some extremely poor snowpack years as well, with 2012 leading the pack here –– featuring some of the lowest snowpacks on recording following the big year in 2011. The 2015 and 2018 years weren't much better, featuring below-average snowpack for most of those seasons as well:
Denver snow stats 2009-10 to 2019
Many (most?) 5280 readers are here for the snow. It won't come as a surprise that the last decade was not a great one for snow lovers along the urban corridor.
Denver, which has a longterm average of 57.1" of snow in a season, has averaged just 48.2" a season since 2009-10 at Denver International Airport. Four of those years featured above-average snowfall, six below average.
The biggest snow season of the last decade came in 2012-13 when the city picked up 78.4" of snow, 21.3" above average. The 2012-13 season and the 2015-16 season were the only two seasons to feature double-digit above average snowfall since 2009-10.
Three seasons were in the chase for the least snowy of the decade, with 2016-17 taking the cake recording just 21.8" of snow (-35.3" below average!). The 2017-18 season and 2010-11 season both also ended with snowfall totals more than 30" below average. These three seasons all landed in the top 10 least snowy for Denver in 136 years of record keeping. The 1888-89 snow season was the only season with less snow than the 2016-17 season, with 21.3" recorded in 1888-89 vs. the 21.8" in 2016-17.
It hasn't been all doom and gloom for snow lovers, however, with a few marks in the positive snow categories as well.
February 2015 became Denver's snowiest February on record with the city picking up 22.4" of snow (average is 7.5" for Feb in Denver). Of course, there were other notable months and storms as well, including the "bomb cyclone" of 2019, and the March blizzard of 2016, which dropped upwards of 15" of snow across most of the metro area.
Also of note, not a single September in the last decade recorded measurable snow in Denver. There was a Trace of snow recorded in 2014, but otherwise nothing. The longterm average for the month is 1.0" for Denver, but you have to go back to 1999 for the last time the city has seen that much (3.1" fell that year).
This year has started quickly in the snow department, landing many cities along the Front Range in the top 5 or even record highest September - November snowfall totals on record. Stapleton through November picked up 29.7" of snow, where on average the site would see 14.0" of snow for the same period. That makes it the 5th snowiest Sept-Nov on record for Denver, with the snowiest being 36.9" set back in 1991.
Colorado temperature above average 7 out of last 10 years
It should come as no surprise that the last decade has been warmer than average for Colorado. Only three years (2011, 2013, and 2019) was the average temperature for Colorado below average. This year has been the coldest of the decade (not pictured below as the year is not over), averaging -0.85°F below average through November statewide. We'll go ahead and count this year as the third year below average as it's likely to end that way. The warmest was 2012 (see above!), which ended an incredible 2.86°F above average. The 10-year average is 0.91°F above the long-term average for the state:
As you can see in the graph above, the warmer than average years not only out-paced the cooler than average years over the last decade but did so at a more considerable departure from average as well. The three below-average years (including this one through Nov) averaged -0.42°F below the long-term average, while the above-average years ran an average of 1.43°F above average.
Of note, no Septembers in the last decade ended with below-average temperatures, coinciding with a lack of September snowfall that we mentioned above.
September was the only month this was true for, although June came close –– June 2019 was the only one below average over the last decade.
The coldest month as compared to average was February, average -0.99°F below average over the last decade:
What did we miss?
There will no doubt be many weather stories we missed, which stand out to you in your memory as you look back at the last ten years? We'd love to hear your stories and experiences in the comments below!
One thing that stood out to me in putting this piece together was just how incredible a year 2019 has been! Fresh on the mind, sure, it's harder to remember individual events from 2010... but this year we saw a new state record low pressure, a new state record high temperature, and a new state record largest hailstone. Not to mention the wild start to the snow season we've seen, and the "coldest" year we've seen statewide in over a decade. Whew!
Anyway, we look forward to your memories, and here's to another wild 10!