Why does upwards lightning use only one path but downward lightning uses multiple paths? My question pops-up from this question &quot;Why does lightning strike from the ground-up&quot; which I consider partially unanswered.
Why do I consider it partially unanswered?
Because only one answer tried to explain why the difference of the several to one paths occur in this phenomenon.

PS: there is another question that arises also
Why does lightning strike from the ground up at this particular location in Earth and has it happened before (at the exact same location)?
Upwards stroke happens when the stepped leader and the traveling spark have already connected. This path then becomes much more conductive than any other paths where the connection hasn't happened yet—because the latter ones have gaps of non-ionized air inside them. This highly conductive path shunts all the remaining stepped leaders, lets the charges quickly cancel out, and thus basically stops propagation of the leaders.