Just prior to 1 pm on July 25, 2000, an 18 year old male was killed by a cloud to ground lighting flash on top of Pikes Peak, Colorado  (elevation 14,110 feet). He was standing in a boulder field very near the top of the mountain (approximately 33 meters [100 feet] from the top). He was the tallest object in a very exposed area. He was with two other friends on the mountain. They were each spaced about 10 meters [30 feet] apart. The one friend closest to the teen who was struck by the flash was thrown to the ground but not injured. The other was still standing after the flash. No thunder was heard prior to this deadly flash.

Data collected from the National Lightning Data Network and displayed on the National Weather Service Pueblo AWIPS weather workstation indicated only 1 flash occurred on top of Pikes Peak. It occurred at exactly 18:56:50 UTC (or 12:56:50 MDT). The flash occurred at latitude/longitude 38.841N/105.040W, or on top of Pikes Peak. A review of lightning data between 12:00 MDT and 1:00 MDT indicated no other flashes occurred within 60 nautical miles of Pikes Peak. Seven other cloud to ground flashes did between 1:00 MDT and 2:00 MDT, but occurred over 6 miles to the south of the top of Pikes Peak.

Below are plots of cloud to ground lightning data in the region of interest on this date. Radar data of composite reflectivity and cross sections are also shown.

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Figure 1. The image at left is the topography of the region (see color label on top of image [values are in thousands of feet]). County names are lableled in image. Pikes Peak is labeled (center of photo). The image at right shows the county borders and county names. The "X" marks the general location of the top of Pikes Peak, in El Paso county.

Figure 2. Lightning flashes plotted between 1700 UTC and 1800 UTC (11 am and 12 noon MDT) on 25-July-2000. Note no lightning was indicated during this hour in Teller or El Paso county. The only lightning observed was in the state of New Mexico. Lightning is indicated by the "-" and the "+" symbols. Teller, El Paso and Pueblo counties are labeled. Pikes Peak is located in far west central El Paso county (see fig. 1.).

Figure 3. Same as figure 2, except for the time between 1800 UTC and 1900 UTC (12 noon and 1 pm MDT). Note the 1 flash in far western El Paso county, on top of Pikes Peak. This is the flash which struck the young man on top of Pikes Peak. According to a NASA scientist, this flash occurred at exactly 18:56:50 UTC, or 12:56.50 MDT.

Figure 4, Same as figure 2, except for the times between 1900 UTC and 2000 UTC (1 pm and 2 pm MDT). Seven flashes are noted during this one hour time period south of Pikes Peak in Teller and Fremont counties.

This case documents a young man who was struck and killed by a lightning flash from a weak thunderstorm on top of Pikes Peak. As shown in the figures above, only 8 flashes occurred with this cell as it developed, moved over, and then moved south of the Pikes Peak mountain area. As shown in Figure 3, only one flash occurred in the Pikes Peak region, and it occurred on top of Pikes Peak. This is the location in which the young man was located. Figure 4 shows seven more flashes occurred in the Pikes Peak region, but these flashes occurred south of the Pikes Peak massif.

Based on the evidence, the first flash from the weak thunderstorm struck the young man. This case emphasizes one must be very alert to lightning storms developing overhead, or nearby.

The remainder of this document discusses the meteorology and science of why this tragic event happened.

Convective clouds become "electrified" when collisions occur between small ice crystals and large hail pellets at temperatures ranging between -10C and -20C. Electrification and Cloud to Ground (CG)  lightning are possible if there are enough hail pellets and ice crystals in this temperature range. most CG lightning flashes occurs as negatively charged hail pellets fall out of the storm (these hail pellets usually reach the ground as a heavy rain). As negatively charged hail pellets get closer to the ground, positive charges gather on the ground beneath the storm (since opposites charges attract). This process, known as induction, causes the electrical potential between the cloud and the ground to build. Lightning strikes if the electrical potential gets high enough.

From a radar perspective, convective clouds start to can produce cloud to ground lightning when radar echoes reach at or about 35 dBz at where the atmosphere becomes -10C or colder. Sounding data taken from Denver Colorado (located 65 miles north of Pikes Peak)  indicated the -10C level was located about 20,000 feet above sea level, or about 15,000 feet above the level at which the sounding was taken (Denver is located about ~5000 feet above sea level, Figure 5). Radar analysis at the time of the strike indicated dBz values between 29 and 34 at the -10C level (Fig. 9). These values are slightly below the known values associated with cloud to ground lightning.

The fact that this weak storm developed above Pikes Peak may have enhanced the development of this isolated flash. The amount of positive charge that gathers on the ground beneath a storm is enhanced on tall objects (such as an isolated mountain). This enhanced positive charge increases the electrical potential and increases the likelihood of CG lightning. For this reason, tall and isolated objects such as mountains, radio towers, skyscrapers, trees, sailboat masts, etc. are frequently struck by lightning, making them dangerous places during a thunderstorm. Pikes Peak, being an isolated tall object, likely played a role in the deadly strike, allowing a weak storm to produce CG lightning.

Below are radar data of the Pikes Peak region in 5 minute increments, starting at 1841 UTC (12:41 MDT) and ending at 1911 UTC (1:11 MDT). The type of radar reflectivity data shown is composite reflectivity (left hand side). A cross section of the cell of interest which produced the lightning flash is shown on the right hand side. The cross section drawn is from south-southwest to north-northeast. The thin red line through the composite reflectivity data shows the cross section drawn. The time of the lightning flash which killed the young man was at 18:56:50 UTC (or 12:56:50 MDT).

Technical Information: The National Weather Service KPUX WSR-88D is located in northeast Pueblo County. The radar was operating in VCP-11 ("Storm mode") during the time of the flash. A total of 14 "slices" of radar data make up the composite reflectivity image. The time (in hours:minutes:seconds) shown in the radar image indicates the beginning of the first radar slice. It takes 5 minutes to complete a composite radar image. The radar is located about 5,000 feet above sea level. The height levels on the cross sections below are measured with respect to sea level. To learn more about the basics of how the WSR-88D works, click here.
 
 

Figure 6. WSR-88D composite radar data (left) at 1841 UTC (12:41 MDT) showing a developing shower over the west sections of Pikes Peak (the top of Pikes Peak is indicated by the yellow X). The fine red line indicates the cross section of the shower (right).
 
 

Figure 7. Same as figure 6 except at 1846 UTC (12:46 MDT). Shower has grown to ~26 thousand feet and is drifting towards the top of Pikes Peak. Maximum dBz is 24-29 dBz range (light rain category). "Heaviest" precipitation is elevated within the cloud.
 
 

Figure 8. Same as figure 6, except at 1851 UTC (12:51 MDT). Shower has intensified slighty, and is now between 29 and 34 dBz. Heaviest precipitation remains elevated within cloud.
 
 

Figure 9. Same as figure 6, except at 1856 UTC (12:56 MDT). Precipitation at this time begins to decend from the higher parts of the cell. The cloud to ground lightning flash occurs at this time, killing the young man.
 
 

Figure 10. Same as figure 6, except at 1901 UTC (1:01 MDT). Heaviest precipitation now reaching the lower part of the storm.
 
 

Figure 11. Radar data and cross section at 1906 UTC (1:06 MDT).
 
 

Figure 12. Radar data and cross section at 1911 UTC (1:11 MDT).

Special thanks to Dr. Steve Goodman, NASA, and Larry Dunn, Pikes Peak Region Search and Rescue, for gathering data for this case. Bard Zajac (CIRA) assisted with the science aspects in this document.