Killer El Reno tornado presented deceptive view to spotters, chasers

The National Weather Service recently reported that the May 31, 2013 tornado that killed four storm chasers presented a deceptive appearance that might have impacted chaser and spotter safety decisions. Well-known tornado scientist Tim Samaras was one of the four chasers who died, despite his reputation for caution.

Below is an excerpt from the NWS Service Assessment: May 2013 Oklahoma Tornadoes and Flash Flooding:

   Several storm chasers reported the visually-deceiving nature of the El Reno storm and its apparent width. Data received, and used with permission, from a chaser compares the visible width of the tornado condensation funnels to the actual width based on RaxPol (Rapid-scan X-band Polarimetric Radar). Although the tornadic circulation was evident on radar, many chasers did not realize they were in, or as close to, the large circulation (W9LW highlighting). During the time of rapid intensification, the forward motion of the circulation increased from approximately 35 mph to more than 50 mph. This speed increase, combined with a sharp left turn and intense inflow winds, made driving away from the tornado difficult (Figures 18–20).

Photo from NWS ser ice assessment.
Figure 18:  Analysis from Gabe Garfield showing “visible vs. actual” tornado width. Red markers approximate visible tornado width and blue markers approximate actual width of the tornadic circulation. Source: Skip Talbot, via NWS service assessment.
Map graphic from NWS service assessment
Figure 19: Visible vs. RaxPol-derived El Reno tornado width. Source: Gabe Garfield via NWS service assessment
Map graphic from NWS service assessment
Figure 20: Estimate of the El Reno tornado speed. Source:  Gabe Garfield and Jeff Snyder via NWS service assessment

This information should provide impetus for all SKYWARN storm spotters to reevaluate their safety procedures as the 2014 storm season approaches. It should serve to remind us all that:

  • Tornadoes can and do make drastic direction and speed changes (don’t expect them to travel in a straight line).
  • Life-threatening conditions can extend well beyond the visible condensation cloud and/or debris cloud, especially in the largest and most powerful tornadoes.

The authors of the service assessment recommended that all future SKYWARN training sessions “reinforce spotter safety and the rules outlined in NWSI 10-1807, The Skywarn® Weather Spotter Program.” That document contains the “10 Golden Spotter Safety Rules,” summarized below (the original 10 rules provide significantly more detail about each rule):

Rule Number 1. ALWAYS operate with your safety as the number one priority

Rule Number 2. ALWAYS follow any and all directives from public safety officials.

Rule Number 3. ALWAYS adhere to the concept of ACES at all times. ACES = Awareness, Communication, Escape routes, Safety Zones

Rule Number 4. ALWAYS activate emergency services BEFORE making a weather report when faced with incidents that cause injuries to civilians.

Rule Number 5. NEVER place yourself in a position to be overrun by, or unprotected from, a storm.

Rule Number 6. ALWAYS be aware of overhead obstructions or objects that could become a safety issue during a storm.

Rule Number 7. NEVER enter a flooded roadway or area for any reason, whether on foot or in a vehicle.

Rule Number 8. ALWAYS treat all downed power lines as energized at all times.

Rule Number 9. ALWAYS obey all state, federal, and local traffic laws and regulations AND practice defensive and safe driving techniques, especially during inclement and night-time driving conditions

Rule Number 10. ALWAYS Operate safely when operating alongside of roadways. Avoid operating within 25 feet of any operating roadway. If you must operate within 25 feet of the roadway, wear ANSI-approved reflective traffic vests or outerwear while operating outside of a vehicle.

No spotter report or storm data is worth any person’s life. Please share this post with anyone you know who participates in storm chasing and/or SKYWARN storm spotting. Buttons below allow convenient sharing on social networks.

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