Park County, Colorado Lightning Incident of 24 August
This research is part of the Colorado Lightning Resource Page, NWS Pueblo, Colorado
"The primary reason for these lightning casualty case studies is to observe where victims were located relative to thunderstorm activity when they were struck".
On 24 August 2003, a 59 year old male motorcyclist was traveling eastbound on Colorado highway 24. At approximately 4:45 pm MDT (2245 UTC), 1.5 miles southeast of Lake George, Colorado, he was struck and fatally wounded by a lightning flash (Fig 1.). After being struck, the bike and rider crossed into the west bound lane and crashed into an embankment on the north side of the highway. A witness who was immediately behind the cyclist in an automobile did not observe any deviant motion of the cycle after the rider was hit. The witness stated; "The bike gradually turned to the left (crossing into the west bound lane) and crashed into the embankment". The witness also stated rain was falling at the time of the flash, and lightning was visible prior to the flash which struck the cyclist. Although the cyclist was still alive when emergency authorities arrived, he succumbed to his injuries while being transported to the hospital. According to the coroner, the cause of death was due to the lightning flash, and not the ensuing crash.
Figure 1. Map of the Lake George, Colorado vicinity. Location of where lightning fatality occurred is marked by the blue "*". The text "Top of hill" and "MP 267" refer to locations of the photos in figures 2 (a) and 2 (b) below. Lake George is located 34 miles west-northwest of Colorado Springs, Colorado. North points towards the top of the map. Map from Delorme. Used with permission.
Estimating the Time and Location of When the Fatal Lightning Flash Occurred
In order to observe which lightning flash caused the fatality, two pieces of information need to be known. The first piece of information is knowing the exact time when the lightning flash hit the victim, and the second is the location of where the victim was struck. Typically, the victims' location is well documented. In this case study, the victim was not moved after the crash, and rescue authorities (Lake George Fire Department) recorded the location of the incident with a GPS unit (in this case, latitude, 38 57' 54" N, (38.96500 N); longitude, 105 20' 08" W (105.33556 W). The location of where the cyclist was actually struck was estimated to be about ~250 feet northwest of the location of where he came to rest. This distance is best estimated from the police report as the cycle was going only about 50 mph (73 feet per second) when it was hit (remember, it was raining at the time), and likely traveled 3-4 seconds on it's own before crashing into the embankment.
Figures 2 (a) and 2 (b) show the stretch of road where the lightning
fatality occurred. Figure 2 (a) is looking northwest along highway 24,
at milepost 267. According to Colorado State Patrol, the cyclist and rider
came to rest 240 feet northwest of the milepost 267 marker, on the right
hand side of figure 2a.
Fig. 2a-b. Photos showing location of where lightning fatality occurred.
Figure (2a) is looking westbound along highway 24 (geographically, the
photographer is looking northwest, see figure 1). The victim came to rest
240 feet from the milepost 267 marker on the right hand side of the photograph
(milepost marker is visible on far left side of photo). Figure (2b) Looking
southeast along highway 24. Photographer in (b) was at the top of the hill
in photo (a), looking back to the southeast. The milepost 267 marker along
with the "Teller county line" sign are barely visible down the road on
the right hand side in photograph (b). The mountain in the background in
photo 2b is Pikes Peak. Click on the photos to enlarge them.
Knowing the exact time of when a lightning flash incident occurs can be difficult at times, especially if it is only one victim and no other people were nearby when the lightning flash hit. However, in this case study, the confidence of when the time the flash occurred (down to 2-3 minutes) is relatively high. The time of the incident was best estimated from the Park county 911 dispatch records. According to Park county Sheriff authorities, the first call came into the 911 Park county dispatch center at 16:47 MDT (2247 UTC).
Once the temporal and spatial information is known, then it is a matter
of reviewing the National Lightning Detection Network (NLDN) data set and
observe which flash occurred at the location and time found above. The
NLDN data set revealed 2 flashes occurred in the immediate vicinity of
where the cyclists was hit, while a third flash occurred nearby around
the same time. The first flash occurred at 2242:28, the second at 2243:14
UTC; and the third at 2246:24 UTC. No other flashes occurred within one
half of a mile of where the victim came to rest in a 30 minute time period
prior to 2247 UTC. Table 1 compares the difference between the location
of where the motorcyclist was struck and the 3 flashes.
Table 1. Location of 3 lightning flashes which occurred within 1/2 of a mile of the incident within a 30 minute time period ending at 2247 UTC (note: there were additional flashes in the area prior to 2247 UTC, but just not within 1/2 mile). Distance between these 3 flashes and where the cyclist came to rest is also shown. The victims' location was measured by rescue authorities at 38.96500N, -105.33556W. The time of the 911 report was 2247 UTC.
Figure 3. Map showing the locations of the 3 cloud-to-ground lightning flashes in table 1. "MP 267" and "Top of Hill" refers to photographs in figures 2a and 2b respectively. The location of where the motorcycle came to rest is also shown. Motorcyclist was traveling from left to right (east bound) on Highway 24 in the map above when struck.
Accuracy of NLDN Data
According to Vaisala Inc. (the organization which runs the national lightning detection network), as of 1998, the accuracy of location of the cloud to ground lightning flash data has a median location accuracy of 500 meters, or a little over 1/3 of a mile (.31 miles or 1637 feet). In 2002, the NLDN network was upgraded, and the accuracy is believed to be even better than 500 meters, but no studies have recently been completed (Cummins 2003, personal communication). It is likely flash 1 did not cause the fatality. The reason for this is two fold. The first is the length of time between the first flash and the time the 911 call was received: this length of time was ~5 minutes. Highway 24 is a major thoroughfare, and motorists driving by seeing the accident would have likely called 911 shortly after the incident occurred. The original eyewitness to the event called 911 "a few minutes" after the cycle crashed (her husband went to assist the cyclist immediately after the crash, and after he could not help him, ran back to the car and his wife dialed 911. It is unknown if this call was the first 911 call to the dispatch center, there may have been other 911 calls reporting this incident from passing motorists). The second reason why the first flash was likely not the flash which caused the casualty is it occurred well east of the the location of where the cyclist came to rest. (The cyclist was traveling east bound when the flash occurred).
Flashes 2 and 3 were in the immediate vicinity northwest of where the victim and cycle came to rest. It is likely one of these two flashes caused the casualty. The reason for this is it is known that the cycle was traveling towards the southeast, was hit by one of these flashes, traveled ~250 feet, and came to rest on the embankment. Flash 2 occurred about 4 minutes prior to the first 911 report, which would match up well with the first witnesses 911 call (if this was indeed the first 911 call). It is also possible the 3rd flash may have also been the flash which caused the fatality. It will never be known which one of these two flashes caused this tragic event, however, it is highly likely that the fatal flash was caused by one of these two flashes.
Information gathered from the police report and the witness indicated it was raining at the time of the event. Composite radar analysis from the closest National Weather Service Doppler Radar, KPUX, at the time of the event is shown in figure 4. From this image, it can be seen that moderate rain was falling at the time of the event. It is possible the rain may have been heavier than what is shown in figure 4 as Pikes Peak was partially blocking the lowest radar beam from the WSR-88D KPUX doppler radar.
Figure 4 also shows the 3 lightning flashes which were discussed in figure 3 above. It can be seen that the lightning occurred in the heaviest rain area.
A ~20 minute loop of composite radar data and 1 minute lightning from 2230-2250 is shown here. Lake George is in the middle of the image. ~1 hour Radar loop of event (Fast internet connection is strongly recommended) this loop also shows composite reflectivity and 1 minute lightning data. NOTE: It takes approximately 5 minutes to acquire one composite radar image. (Click here to learn more about Doppler radar).
Figure 4. Composite reflectivity overlaid with the 3 lightning flashes discussed in this study.
Additional Lightning Analysis
Lightning data prior and up to the fatal flash was analyzed to see if the cyclist may have known there was a threat of lightning in his vicinity. The cyclist was traveling towards the storm in figure 4 and he eventually entered into it. Lightning data from 2230 UTC to 2245 (Figure 5) shows there was 9 cloud to ground flashes which were likely in the cyclist view as he traveled southeast down highway 24. In addition, there is also a high probability that cloud to cloud flashes were also occurring during this time (The NLDN can only detect cloud to ground flashes. It is estimated that for every cloud to ground lightning flash, there are 10 cloud to cloud lightning flashes). It is possible that the cyclist may have never seen any flashes before he was hit (due to poor visibility due to the rain) or have heard any thunder (due to his helmet), however, given the fact that an eyewitness who was immediately behind the cyclist reported cloud to ground flashes were visible prior to the cyclist being struck, it is likely that the cyclist knew that lightning was in the immediate area.
Figure 5. Lightning plot showing cloud to ground flashes across the greater Lake George region between 2230:00 and 2245:00 UTC 24 August 2003. All of these flashes (9) occurred south and east of Lake George, Colorado. The cyclist was traveling southeast on highway 24 when struck. Note: flash 1 and 2 in Table 1 are included in this image, flash 3 is not shown as it occurred at 2246:24 UTC.
Additional Weather Analysis
Satellite imagery of the time of the event indicated "cold cloud tops"
during the time of the fatal lightning strike (Figure 6). Cloud top temperatures
were in the -40 to -50C range. This is typical of cloud tops which produce
lightning. Visible satellite imagery at the same time is shown in figure
7. Figure 8 shows basic meteorological maps from the RUC model close to
the time of the event.
Fig 6 Infrared satellite imagery at 2245 UTC along with 15 minute lightning data ending at 2245 UTC.
Fig 7. Visible satellite imagery at 2245 UTC along with 15 minute lightning data ending at 2245 UTC.
Fig 8: RUC computer model analysis over Colorado at 2200 UTC. Click on image for larger view.
On 24 August, 2003, a motorcyclist who was riding in a moderate rain storm while lightning was occurring was struck and killed by a lightning flash. This flash occurred in a relatively open area along highway 24 southeast of Lake George, Colorado. Reports from an eyewitness indicated lightning was visible prior to the fatal flash, and rain was occurring at the time.
This case shows that motorcyclists can be hit by lightning while riding on a motorcycle. It is recommended that motorcyclists should be aware of their environment (Is lightning occurring nearby??) and to seek safe shelter if lightning is observed. It should be assumed that any rain shower in Colorado in the Summer months has the capability of producing cloud to ground lightning.
Lightning safety rules can be found here. Please practice lightning safety.
Questions regarding this document should be addressed to the lead author (email).