DENVER — It's hard to believe it's been a decade since devastating floods ravaged parts of the Front Range in September of 2013.
Normally, we have stormy weather every month of the year except for the month of September.
For years, Denver7's Chief Meteorologist Mike Nelson used to tell brides "if you're having an outdoor wedding, get married in September. It's the quietest month."
But in September of 2013, it was a different story. The floods that hit the Front Range and northeast plains were unprecedented.
Here's what happened.
A weather front stalled across the state from about the 10th to the 15th of September 2013. That front combined with a monsoon flow of moisture coming in from the south. That tropical moisture produced high amounts of thunderstorm activity and heavy rainfall.
The heaviest rainfall totals were seen in parts of Larimer County, Boulder County, and another band that went through Aurora and extended up to the Firestone and Dacono area. That rainfall then drained into the South Platte River Basin. That's why we had such terrible flooding all the way along the South Platte and out to Sterling and beyond.
Some areas received more than a foot of rain. Parts of Boulder County saw 15 inches of rain, other areas got up to 18 inches.
More than a foot of rain dropped on Bellvue with Estes Park receiving nearly a foot of rain. Jamestown's rain gauge recorded 13.47 inches during the historic event.
Southeast Boulder got a whopping 21 inches, and Nederland saw over a foot, all flowing downhill to the rivers in Boulder County.
The flow patterns on the South Platte River reached 13 feet. Normally, the South Platte levels only reach between 2.5-3 feet. The flood stage starts at 10 feet.
Downtown Denver didn't see quite that much, but at City Park, there was still over 7 inches of rain.
Finally, the monsoon flow weakened, and the front moved to the east on the 15th of September, letting up on the intense rain and flooding.
But the damage was left behind.
To many, it was reminiscent of the Big Thompson floodthat occurred at the end of July 1976.
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David Barjenbruch, senior meteorologist at the National Weather Service in Boulder, described the Big Thompson flood as a more localized, heavy rain-producing thunderstorm that spurred the 1976 catastrophic flash flood. But that event mostly affected just the Big Thompson Canyon.
In comparison, the 2013 northern Colorado flood was more widespread, over a larger area. And this heavy rain event lasted over a longer duration of time- approximately 30 hours, Barjenbruch explained.
Typically, we don't see more than an inch of rain in the entire month of September. The monsoon moisture was more typical of what we would see in the middle to late part of the summer in July and August.
"We had various sources of moisture, one of those being the Gulf of Mexico. Rich low-level moisture was available in the atmosphere in combination with some subtropical moisture that was coming off of the Baja," Barjenbruch said.
Another important feature of this storm was what Barjenbruch called a mesoscale convective vortex. He described it as "turning winds into the foothills, which created or enhanced the upslope in the region." The National Weather Service defines upslope as an "increased chance of thunderstorm development if the air is unstable."
Those conditions fueled the persistent, heavy rainfall in Boulder and Larimer Counties, the evening of the 11th through the 12th of September 2013.
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While some people ask Nelson if the 2013 flood happened because of climate change, he said it could be attributed more so to a bad combination of weather.
Many of the studies that were done in the wake of the 2013 storm found climate change was not really the driver of that flood. Nelson said there's an awful lot of things we can attribute to global warming and climate change, but this might have just been one of those rare weather events.
"Perhaps it's just once in a lifetime event. Let's hope it is. But the time to be prepared for flooding is anytime during those spring to summer, to late into the fall, months here. We're getting toward the tail end of our of our flash flood season, but it's never too early to prepare for that next flood," Barjenbruch said.
We all know how unpredictable Colorado weather can be, so there's no way to know for sure if we could see another storm of this kind in our lifetime.
But "that said," Barjenbruch told Denver7, "We are continuing to make advances in the meteorological world in the forecast business, where we have higher resolution modeling available that allows us to capture some of these local, what we would call orthographic- or storms that produce locally heavy rains against the Front Range."
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