Dan Robinson
EF5
Since a couple of chasers have had high-profile (and excellent, by the way) videos of upward lightning go viral this season, I thought it might be a good subject for a thread. I have a big fascination with this type of lightning (well, ALL lightning to be truthful) and have spent a lot of time documenting it.
A couple of points:
- Upward lightning isn't really "rare". It happens with nearly every thunderstorm passing over a tall tower or building (above 600-800 feet tall). Every thunderstorm in a metro area produces it. What is rare is a purely "natural" upward lightning flash. Most upward lightning we see is man-made-structure triggered, that is it would not happen without the tower or skyscraper there. The only places where upward lightning occurs naturally is with high, isolated mountain peaks, I am aware of only one photo of such an event (the link is on my upward lightning page).
- The stratiform precip region of an MCS is where most upward discharges occur. The best place to observe this type of lightning is in the trailing precip regions of squall lines. The squall line need not even be severe - even marginal storms will produce upward flashes. Strikes are virtually guaranteed to any tower above 800 feet AGL. Multiple hits are typical, and simultaneous strikes to multiple towers are very common.
I compiled all of my knowledge, videos and photos on upward lightning to this page on my site:
http://stormhighway.com/tower.php
A couple of points:
- Upward lightning isn't really "rare". It happens with nearly every thunderstorm passing over a tall tower or building (above 600-800 feet tall). Every thunderstorm in a metro area produces it. What is rare is a purely "natural" upward lightning flash. Most upward lightning we see is man-made-structure triggered, that is it would not happen without the tower or skyscraper there. The only places where upward lightning occurs naturally is with high, isolated mountain peaks, I am aware of only one photo of such an event (the link is on my upward lightning page).
- The stratiform precip region of an MCS is where most upward discharges occur. The best place to observe this type of lightning is in the trailing precip regions of squall lines. The squall line need not even be severe - even marginal storms will produce upward flashes. Strikes are virtually guaranteed to any tower above 800 feet AGL. Multiple hits are typical, and simultaneous strikes to multiple towers are very common.
I compiled all of my knowledge, videos and photos on upward lightning to this page on my site:
http://stormhighway.com/tower.php
