A Night To Remember: The Ft. Collins Flood
by Slim Ray and John F. Weaver
..."There are several cars underwater, both right side up and upside down, with people in them..."
..."A lady in a gray sweatshirt was just swept off her feet on Shields St. and disappeared down Shire Court screaming ..."
..."Two mobile homes just erupted in flames in the Johnson Mobile Home park..."
[two minutes later] "The train has just derailed! the train has just derailed!"
[twenty seconds later] "Johnny's Liquor has just exploded, there is a heavy smell of gas throughout the area..."
[two minutes later] "Attention all units!...we have just learned that there may be hazardous materials being transported by the train..."
..."Dispatch, several 40x60 trailers are now moving down Spring Creek toward the College Ave bridge...there is screaming coming from inside some of the floating trailers..."
While this may sound like a "B" Hollywood disaster movie, it really happened in Fort Collins, Colorado on the night of July 28th 1997. These incidents are only a small sample from the total on a night when the EMS system suddenly found itself overwhelmed by the forces of nature. By midnight, five people were dead and sixty-two injured. Many others barely survived. This is the story of what happened that night and what lessons the city learned from it.
At the Ft. Collins dispatch center that evening the swing shift came to work in a steady light, drizzle. Dispatcher Tom Wright, on the graveyard shift, drove in through what he thought at the time seemed like just a little too much rain, arriving at 9:30 p.m. Then he walked through the door of the Fort Collins dispatch center into "total chaos." There were frantic conversations on seven phone lines, plus chatter to and from two fire channels, three PD channels, an ambulance channel, and a dive channelall going at once.
Heavy rains are rare in the high Plains. The city of Fort Collins' annual average yearly rainfall is 15 inches, most of which occurs in the late fall or early spring. When heavier rains do come, they almost always spell trouble. Problem areas include steep runoff gradients, easily saturated soils, and paving in urban drainages. The city was aware of the problem and had made considerable mitigation efforts in the years preceding the flood.
From the foothills on the west side of Fort Collins to Interstate 25 some six miles to the east the elevation drops over 300 feet. Over the years, runoff waters have carved broad, shallow, natural drainage basins onto the land. Two of the largest of these are called the Canal Importation and the Spring Creek basins. A confusing tangle of creeks and irrigation canals crisscross the drainages.
To deal with emergencies Fort Collins has the Poudre Fire Authority (PFA), a consolidated fire protection and emergency services organization with 111 full-time firefighters, all of whom had undergone some basic flood rescue training. Larimer County also has a twenty-man dive team, with volunteers from surrounding communities available as needed.
Fort Collins, in short, had done its homework. They were well prepared for a flood, or so they thought.
By late afternoon on July 27th, the air over the Rocky Mountains foothills had become so warm and moist that it compared favorably with tropical air masses that Colorado State University scientists had recently measured over the southwest Pacific. At 4:30 p.m. it began to rain, starting as a slow drizzle, then increasing throughout the night to a steady, heavy rain. By noon on the 28th, the western half of the city had received three to four inches of water, and areas 8 miles to the north upwards of ten inches, saturating the soil throughout the region.
The rain slowed to a drizzle just after noon, but all of the creeks and irrigation canals in the city were now full. The city's new emergency manager, Glenn Levy, alerted the Dispatch Center and Ft. Collins Storm Water Utility administrators. He also talked with PFA, asking that they make their resources available for pumping and sandbagging. Unfortunately, a three alarm house fire that afternoon pulled away many units that would normally have been available.
The rain began to pick up again just after 5:00 p.m. A series of individual rain cells formed southwest of the city, then moved slowly off toward the north-northeast, interleaving drizzle with longer periods of extremely heavy rain. The showers were so heavy that during the most intense periods the noise interfered with normal conversations indoors. One woman remarked that rains sheeting off her roof looked like she was standing behind a huge waterfall.
At the dispatch center, hints of trouble began to show up by 7:00 p.m., but the situation really didn?t begin to deteriorate until just before 8:00. There were several calls about flooded basements, and at first dispatchers sent PFA engines to help with pumping. Within half an hour, however, the number of flooded basement calls vastly exceeded resources. Dispatchers now had to inform callers that there was nothing the city could do.
Phone and radio traffic continued to increase. Just after 8:00 p.m. the average number of calls from the public increased from 6-8 over a 15 minute period to about three per minute. Fire and police radio traffic "segments" (a short radio communication between a responder and dispatch) jumped from just 2 between 8:00 and 8:14, to 16 in the period from 8:15 to 8:29.
Until now dispatchers had been holding their own. But the call volume kept increasing, calls started stacking up, and the situation began sliding out of control.
Reports of flooded intersections and basements now became mixed with other, more ominous calls. One caller reported a 20 acre field in front of Hughes stadium was full to overflowing; another that the basement was flooded and her daughter was trapped; another that kids were playing in the dangerous water; and another that sewer lids were blowing off and water spewing out. The water was also setting off automatic fire alarms all across town. Just before 8:30 p.m., a caller from a stable near Spring Creek reported that the normally 8 foot wide, 6 inch deep waterway was now running 8 feet deep, flooding the barns. Firefighters arrived on scene to find the creek more than a hundred feet out of its banks, and spent the next half hour helping to move horses to safety.
For the most part, though, PFA spent their time during this period checking on fire alarms and responding to basement calls that now included walls ready to collapse, pilot lights out with a smell of natural gas, and "sparking" electrical outlets. Police tried to keep the public out of deepening water on roads and intersections. Traffic and road problems, however, were actually increasing. College students and others began showing up with inner tubes and boogie boards to play in the runoff. Some drivers with SUVs came out to "test" their vehicles.
Still, the situation, though chaotic, seemed manageable. But Mother Nature wasn't finished yet. A large storm, some 40 miles to east, suddenly produced a dome of cold air that deflected and accelerated the air on its northern fringe by nearly 50%. Now the warm, moist airfuel for thunderstormsraced westward in a narrow jet, ramming the richest air across the southern half of Fort Collins and into the Spring Creek Basin. Rain rates nearly doubled, and what had been a series of slow-moving cells became a single, large and very intense tropical rain storm stalled over the Spring Creek and Canal Importation Basins.
Ft. Collins now found itself well outside the boxfar beyond what any training had covered. Resources were being spread too thin. PFA had seventeen units in service (11 engines, 2 "mini's", 2 trucks, a search and rescue squad, and 1 tender), with 36 firefighters on duty, and forty-one more who came in on 2nd and 3rd alarm page.
It wasn't even close to what they needed.
As the water rose, boogie boarders toppled into the fierce currents and had to be rescued. Dozens of automobile drivers were pulled from cars, and a police officer rescued a woman who was holding onto a bus bench with one hand and a baby with the other. According to the officer, the baby was "bouncing up and down on the top of three-foot-deep white water rapids." The water surged onto the campus of CSU, inundating the student center and campus library and soaking nearly a half-million books.
Dispatch consoles lit up as communications nearly tripled again. Phone calls were now coming in at one every 8.5 seconds, and radio traffic was nearly continuous. There were 104 incoming calls to the E-911 and non-emergency police phone lines, and 109 separate radio "segments" on police and fire radio channels between 9:45 and 10:00 p.m. alone.
The system was now brokenthere was no way to accept, triage and assign calls at seven per minute, much less find available rescue units to handle them. In fact, field units were having problems of their own. The water had blocked many access roads, cutting the city in half, then in half again. Radio batteries were wearing down, police cars stalling in the deep water, and communications in general deteriorating. Double and triple radio traffic became the norm. Firefighters would stumble onto emergency situations on their own, more urgent than the calls they were on, and couldn't report the change in mission to dispatch.
By 10:00 p.m., the combined flow from Spring Creek, general street runoff, plus runoff from the Canal Importation Basin, was sending a total of 8,250+ cfs of water directly into a 50 acre detention pond. The eastern side was bordered by a 19 foot high railroad embankment with several culverts in it to allow excess water to move eastward in a controlled fashion. This detention facility had been designed to collect and hold nearly double the predicted 500-year flood overflow.
Word of the final phase of the disaster began to filter in around 10:30. Callers from houses just east of the railroad embankment reported that Spring Creek was beginning to flood nearby houses. Only one fire engine was available, and it headed toward the scene at 10:44. While it was still on its way, with most rescuers working furiously in a three-to-four square mile area to the west, severe turbulence and enormous water pressure caused the 12x14 foot culvert under the railroad bed to literally blow out. A few minutes later, the water (which had continued to rise despite the release of 3,300 cfs through the failed culvert) began overtopping the railroad embankment. In a near-perfect example of Murphy's Law, a freight train had begun crossing this section of track minutes before.
The roaring water derailed the train and surged into two trailer parks next to the tracks, blowing one mobile home to pieces and flooding the rest. Several people who'd driven through there just twenty minutes earlier reported having seen only rain-dampened roads. By 11:00 p.m., 8 foot deep waters were floating trailers and sweeping victims into the 12 foot deep Spring Creek channel. Broken gas lines ignited three mobile homes which burned fiercely in the midst of the flood. A nearby store exploded from leaking gas. Four women in the trailer park drowned, and downstream from the trailers another woman drowned trying to rescue a pet.
By the next morning the waters were gone, and the city and its residents began cleaning up and assessing the damage.
The Fort Collins flood taught a number of hard lessons. Foremost was the need for "weather awareness" leading to early recognition and warning of flooding. By the time reports of flash flooding have filtered in through the normal reporting system, it's almost always too late for evacuation and rescue efforts to begin. There are too many incidents, units are blocked by flood waters from many locations, and there is no time to deploy. The critical link between warning and rescue is the emergency dispatcher.
The Fort Collins Office of Emergency Management has now formed working partnerships with agencies such as the Federal Emergency Management Agency (FEMA), the National Weather Service Office in Boulder, Colorado, and several others. The goal is to try to mitigate the effects of disasters in advance and streamline communications before, during and after catastrophic weather events. Some issues include:
- Improved communications with the National Weather Service (NWS) during dangerous weather situations. The city has installed an NWS Emergency Manager's Weather Information Network (EMWIN) that receives weather products automatically. The EMWIN system can send messages via electronic mail, to a printer, or can trigger electronic pagers based on "keyword" cues.
- Fort Collins has installed a prototype system called Local Area Data Acquisition and Display (LDAD) that allows them to transmit stream and precipitation data back to the NWS.
- Electronic precipitation and stream flow gauges have been installed across the city, especially within flood-prone areas. This network is transmits information automatically to the Emergency Operations Center, giving a real time view of rainfall amounts and stream levels.
- A real time flood inundation mapping and notification system integrates newly acquired, high-resolution topographic data with weather forecasts; hydrology experts; and stream and precipitation data. It uses the combined information as input to a computer-based runoff model, and provides real time flood forecast information to emergency managers as the event unfolds.
The city now has a paging "tree" that brings various city officials and response organizationsincluding the E911 dispatch officeto readiness when hazardous weather threatens.
- Natural Disaster Information Cards have been designed that cover a variety of natural disasters. The cards are similar to those used for EMD. Designed locally, they have been reviewed and edited nationally and include input from NOAA, FEMA, and the American Red Cross. These cards allow dispatchers to quickly sort out the serious incidents from the trivial and obtain information vital to rescue units. The cards can be found on-line at:
- A Reverse 911® dialing system has been installed that allows the emergency management office to send a pre-taped message to upwards of 200 homes per minute over the telephone. The specific threat area within the city is selected from a computer map at a dispatch console, allowing city personnel to 1) quickly warn residents in endangered areas, 2) direct the resident to public sources of information 3) help control call volume by specifying when and when not to call 911.
- A new, low-power AM radio station has been installed to help keep the public informed during disasters. This will be advertised locally at regular intervals, and mentioned as an information source on the Reverse 911 message.
These steps will help Ft. Collins and other cities implement education, mitigation, communications, and recognition of critical threats when a weather disaster strikes.
© Slim Ray and John F. Weaver 2000 All rights reserved
The article originally appeared in 911 Magazine