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Marshall Fire - December 30, 2021
On December 30, 2021, the most destructive wildfire* in recent Colorado history occurred. The Marshall Fire, a large grass fire east of Superior, Colorado, broke out in the mid-morning hours of December 30th. Record winds at up to 100 mph and a very dry fall contributed to the conditions that allowed the fire to spread very quickly eastward toward the cities of Louisville and Superior. Figure 1 shows a very high level overview of the approximate fire starting location and the areas that were impacted in Superior and Louisville. Boulder County has maintained an incident website that summarized the total structures destroyed and the overall eventual perimeter of the fire. Figure 2 shows a high level view of the fire’s extent and structures burned.
* Most Destructive in terms of property damage, not acres destroyed/burned.
An excerpt of the Boulder County Website Summarizes the damage as follows:
Residential Structures:
- City of Louisville: 550 structures destroyed, 43 structures damaged; actual value** of residential damage is approximately $229,199,184
- Town of Superior: 378 structures destroyed, 58 structures damaged; actual value of residential damage is approximately $152,757,462
- Unincorporated Boulder County: 156 structures destroyed, 48 damaged; actual value of residential damage is approximately $131,255,944
- Updated totals confirmed to date countywide are 1084 residential structures destroyed and 149 residential structures damaged. Total countywide actual value** of residential damage is estimated to be $513,212,589.
- City of Louisville: 4 structures destroyed, 14 structures damaged
- Town of Superior: 3 structures destroyed, 14 structures damaged
- Unincorporated Boulder County: 2 structures damaged
Figure 1 - Overview of the area impacted
Figure 2 - Boulder County summary of the structures damaged/destroyed
As the fires burned during the afternoon of December 30th, evacuations began occurring throughout the unincorporated area of Boulder County and the cities of Superior and Louisville. Very quickly thereafter, structures began to burn in the two cities. Superior had large scale fires happening through the night of December 30th into the morning of December 31st. As the fire was raging, Town staff were shutting off curb stops at each burned property in an attempt to keep water available for fire fighting activities. However, with the speed of the fire, many fire-fighting locations were quickly evacuated and certain hydrants kept draining the system. As the fire continued, the city began losing pressure, and a boil advisory was issued for the entire city of Superior, affecting approximately 17,000 people.
During the same time, the city of Louisville also was battling to maintain water pressure throughout their high pressure zone due to multiple neighborhoods being destroyed. As the fire progressed, the city was under the threat of running out of water because of the number of hydrants running. Also, large scale power-outages were occurring to avoid further dangers as power poles were destroyed. Therefore, Louisville made the decision to allow water to gravity feed their system from their eastern-most water treatment plant, without any chemical treatment (coagulant or chlorine). With untreated raw surface water entering the system, the CDPHE issued a boil advisory for the entire City, affecting approximately 20,000 people.
Additionally in unincorporated Boulder County, the East Boulder County Water District was issued a boil advisory due to pressure loss and fire damage. Power outages also caused advisories that were not due directly to fire damage at several small water systems. It is important to remember that in these cases, the water districts could not have done anything differently to avoid these boil advisories. In fact, the water staff were heroically working to keep water flowing to help fight the ongoing fires while some of them had even lost their own homes.
As the fires were extinguished and the mandatory evacuation orders were lifted, the public was anxious to get back into the area to begin the recovery process. It is important to note that each city individually did an excellent job on informing the public of the boil advisories. Boulder County was also instrumental in assisting with public communication and the media.
During the first week of January, the public water systems worked very quickly and thoroughly to fully disinfect and flush their distribution system. There were over 150 miles of distribution pipes to flush. The water systems worked in close coordination with each other and with CDPHE to execute this flushing and disinfection. The advisories were lifted on January 6, 2022. The professionalism and dedication of the water operations staff at these utilities was excellent and commendable during this challenging event. The community and state owe a debt of gratitude to the utilities as they worked through the Marshall Fire event. Governor Polis expressed his deep appreciation for all the utilities did during this very challenging time.
Figure 3: Example of a destroyed neighborhood
Figure 4: Example of a partially destroyed
After the immediate warning of the water being unsafe to drink was addressed, additional issues arose in the weeks following the fire. There were concerns about possible contamination from burned buildings, concerns about tastes and odors in parts of the water systems, and ongoing tracking of cross connections that was necessary. Water utility staff were proactive in sharing information with their decision makers and the CDPHE, and the public was kept in the loop via the city websites as well as public meetings.
In the coming weeks, we will publish additional information about the large-scale boil advisories and additional issues that have arisen as a result of the Marshall Fires and other events of 2021. These topics will include:
- How do you effectively warn thousands of people about a boil advisory?
- What if a portion of your community does not speak English?
- Fires that burn primarily structures (as opposed to forests) may release VOCs!!
- Cross connection tracking post-fire to avoid backflow events.
➽ Tyson Ingels, P.E Lead Drinking Water Engineer
