Coming up with a risk level classification of chase maneuvers

Dan Robinson

Staff member
Jan 14, 2011
2,392
2,051
21
St. Louis
stormhighway.com
I'm using the whitewater rafting class levels as a template for categorizing the risk of chase maneuvers. This is my first attempt at populating these classes. Feel free to add your input/revisions!

* high visibility/classic supercells

Class VI: Among all chasers who perform these maneuvers, there is an average of one accidental tornado impact every 2 seasons. High risk of death or injury even for experienced and adequately-equipped chasers.

- Entering the outer circulation of violent or wedge-sized tornadoes*
- Approaching violent rain-wrapped tornadoes
- Entering rain-filled RFD toward an area with an intense radar-indicated circulation and/or large, violent tornado reported

Class V: Average of one accidental tornado impact every 4 seasons. Requires absolute mastery of chasing execution and adequately-equipped vehicle.

- Approaching violent or wedge tornadoes within 100 yards of the outer circulation*
- Entering rain-filled RFD with reported tornado and/or strong radar-indicated circulation
- Positioning within the notch of HP supercells in extreme tornado environments
- Approaching strong rain-wrapped tornadoes
- Entering the outer circulation of strong tornadoes*

Class IV: Average of one accidental tornado impact every 6 seasons.

- Positioning under the meso in extreme tornado environments
- Positioning within the notch of HP supercells in strong tornado environments
- Approaching weak rain-wrapped tornadoes

Class III: Average of one accidental tornado impact every 10 seasons.

- Approaching strong tornadoes within 100 yards of the outer circulation*
- Approaching violent tornadoes within 1/4 mile*
- Positioning within the notch of HP supercells in moderate tornado environments
- Positioning under the meso in strong tornado environments
- Entering any rain-filled RFD toward a developing/developed meso
- Approaching/entering outer circulation of weak tornadoes*

Class II: Average of one accidental tornado impact every 12 seasons.

- Approaching strong tornadoes within 1/4 mile of the outer circulation*
- Approaching violent tornadoes within 1 mile*
- Positioning within the notch of HP supercells in weak tornado environments
- Positioning under the meso in weak tornado environments
- Crossing low-visiblity (rainy) RFD/hook slicing to gain visual of a meso/tornado
- Core punching from the north through the forward flank of a supercell
- Approaching strong tornadoes within 1/2 mile*
- Approaching outer circulation of weak tornadoes*

Class I: Average of one accidental tornado impact every 20 seasons.

- Positioning either behind or 90 degrees right of the track of supercells and tornadoes
- Positioning more than 5 miles ahead of supercells/tornadoes, never crossing their path
- Staying more than 2 miles from weak tornadoes
- Staying more than 5 miles from strong to violent tornadoes
 
Last edited:
Sep 29, 2011
617
525
21
47
Fort Worth, TX
www.passiontwist.com
I think the "danger" aspect is less/more regarding a chaser's relative position to the storm/tornado than just absolute distances. Given a high-visibility classic supercell, you can maneuver extremely close with steady-state tornadoes and still be extremely safe, if your position relative to the tornado track puts you out of the path. Anything HP at all, all bets are off. It's all Class 6 to me LOL. I'll get in the cage with the bear, but only if I can see the bear.
 
  • Like
Reactions: James Wilson