When a slow-moving front collided with warm, humid monsoonal air from the Gulf over Colorado the week of Sept. 9, 2013, it resulted in heavy rain that re-fired on an almost daily basis from New Mexico to Colorado and southern Wyoming.
Thunderstorms along the Rockies and foothills are common during the summer months, but typically, the storms are short-lived, pushed along by strong winds high in the atmosphere. The convergence of a large swath of tropical moisture over the Rockies (referred to as the Monsoon by locals), a large area of high pressure over the Midwest and a storm in the upper atmosphere over the Great Basin in September is unusual.
The stalled system created a long-lasting storm that dumped excessive amounts of rain, which in turn caused catastrophic flooding along the Front Range (a mountain range of the Rockies running north-south from southern Wyoming to Colorado) from Colorado Springs north to Fort Collins. Rainfall totals recorded by the Community Collaborative Rain, Hail and Snow Network from Sept. 9 to15 show significant totals in Aurora, Boulder and Estes Park. Several locations in Boulder recorded 15-20 inches, with one area receiving 16.9 in. These numbers approximate Boulder County’s average annual precipitation (20.7 in.) and have been observed only a few times in the past century.
Assessing The
Damage
Estimates count as many as 19,000 homes damage and 2,000 destroyed across Colorado. The Colorado Department of Transportation estimates that at least 30 state highway bridges have been destroyed, with another 20 seriously damaged. Bridge and road repairs are expected to run into the millions.
U.S. Route 34 and U.S. Route 36, the main highways through Estes Park, were severely damaged, isolating hundreds of residents, who also were affected by the destruction of sections of Fish Creek Road and all nine crossings across Fish Creek. In addition, damaged sewer lines dumped raw sewages into the creek and the Big Thompson River.
Hundreds of miles of washed-out roads, as well as freight and passenger rail lines that were washed out or submerged, left many small mountain towns completely cut off. Extensive road damage in Big Thompson Canyon cut off access to Drake, Glen Haven and Cedar Park.
More than 1,120 sq. mi. (2,901 sq km) in Larimer County were affected by the flooding, which destroyed 1,500 homes and 200 businesses and damaged an additional 4,500 homes and 500 businesses.
First Response
Larimer County was one of three areas the First Response Team concentrated on, along with Lyons and Longmont.
“We arrived as the floods were happening,” said Tad Agoglia, founder of the nonprofit organization that provides emergency aid to areas hit by disasters. Since May 2007, the team has helped thousands of victims at numerous sites across the country. Agoglia himself was designated a Top Ten Hero in the 2008 CNN Heroes contest under the Community Crusader category. He received a Jefferson Award in 2010.
The team’s first stop was Lyons, where, Agoglia said, “the neighborhoods now had rivers. It was shocking to see. It was amazing how the water came down the mountains and found new paths.”
The town of Lyons is one that was isolated when several earth dams along the Front Range burst or were over-topped, allowing the St. Vrain Creek to flood.
“The roads were gone,” Agoglia said. “The base of the roads was just gone.”
So was vital infrastructure: sewer, water lines and power lines.
“So many bridges were destroyed, the mountain community was cut off. There was no way to get to them.”
Usually, the team focuses on cleanup and clearing of trees and debris. The difference between this and other emergencies is that the roads were simply gone, washed away. To create access for other emergency responders, first it had to fill in the washed-out roads with stone, sand and dirt.
“We filled in rivers with stones so the fire trucks could drive across,” Agoglia said. “Our initial role was to make temporary crossings with Cat equipment.”
Once the team could get in, it discovered that the city of Lyon had no electricity and that many buildings were destroyed. The team installed a Cat generator at a school so the local government and emergency officials such as the National Guard and the Boulder County Sheriff Department had a place to work. The team erected its fleet of Allmand light towers for safety and to discourage looting.
Wagner Rents, the local Cat dealer, loaned First Response Team $250,000 worth of equipment to use.
“We’re thankful for the Cat network,” Agoglia said. “It’s important for us to have support from the Cat dealers. Their support is vital for our work. It’s a great partnership.”
Next Steps
Colorado Gov. John Hickenlooper declared a disaster emergency in 15 counties. President Barack Obama also declared a state of emergency, which authorized federal search and rescue teams, as well as supplies such as food, water, cots, generators and emergency flood control measures. The president declared a major disaster specifically for Boulder County; this allows federal recovery assistance, including temporary housing, home repairs and low-cost loans.
More than 11,000 have been evacuated, but the Colorado Office of Emergency Management reported eight deaths and hundreds more unaccounted for. At least 1,750 people and 300 pets were rescued by air and ground, although rescue efforts were hampered by continuing rain and a low cloud ceiling, which temporarily grounded National Guard helicopters.
First Response Team spent two months performing vital crisis assistance. After the emergency phase, they began going home-to-home to the 20,000-plus affected homes in Longmont to remove furniture and dig out mud from basements after 4 to 8 ft. (1.2 to 2.4 m) of mud mixed with large boulders.
“It was overwhelming for homeowners,” Agoglia said. “It was not easy work; they need heavy equipment to clear it out.”
Such heavy-duty work requires expert assistance; as Agoglia said, a shovel and wheelbarrow won’t suffice.
The team provides more than mere manpower, however.
“It’s important for people to have help,” Agoglia said. “Many lost everything, and most have no insurance to help. After the flood, people return and ask ’Where do I begin?’ As we do the work, people see things getting back to normal. It allows them to transition from an overwhelming abnormal situation to a new start. Our help is free — a real gift. It gives people hope.”
The flood victims need hope. In addition to their personal crises, they will experience the economic impact of the flooding of low-lying agricultural land in northeast Colorado. Significant crop damaged is expected from flood waters inundated fields and pastures and now has no way to drain, so remains standing in the fields.
In addition, hundreds of oil and gas wells in the Denver Basin were shut down. Several were under the rushing flood water, resulting in broken lines and loss of storage tanks swept away. One spill from flood-damaged storage tanks in Milliken has already been reported: 5,250 gal. (19,873 L) of crude oil were released into the South Platte River.
It will take years and millions of dollars to recover from the devastation wrought by this 100-year flood.
Historic Floods
Flash floods in Colorado are uncommon, but not unusual. According to the National Center for Atmospheric Research, since 1864 there have been at least 22 floods with a value of $2 million or more (in 1999 dollars). Other significant floods have occurred in the past 50 years, most notably in 1965 and 1976. The 1965 flood from June 14 to 20 took 21 lives and caused $500 million in damage, after 12 in. of rain fell overnight near Fort Collins. During the Flood of July 1976, stationary storms dropped 12 in. of rain in three hours and 8 in. of rain in one hour over the Big Thompson River Canyon, according to the National Weather Service in Boulder. A single wall of water rushed downstream, leading to 145 fatalities and $40 million in damage.
The September 2013 flood was longer-lasting and more widespread than either of the two major floods preceding it. Flood waters spread across a range of 200 mi. (322 km), stretching into New Mexico, southern Wyoming and western Kansas. Damage extended across 2,000 sq. mi. (186 sq km). All-time record or near-record precipitation was recorded during the week of Sept. 9 to 15 across the Front Range.
According to a report by the Cooperative Institute for Research in Environmental Sciences (located in Boulder and made up of scientists from the National Oceanic and Atmospheric Administration, the University of Colorado and Colorado State University), “In the context of the entire Front Range this was a rare precipitation event, especially for September, and in some respects unprecedented.” The event “was likely a 100-year flood (or more accurately: a 1 percent probability per year flood).”
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