Looks to me like a Nuke went off.
This was posted on Youtube on August 5, 2019.
Comment from Youtube (not sure if this is accurate or not ... anyone else know?)
Once again....what is this..the 8th incident of russian military hardware going up in flames? And they all have been some serious explosions equivalent to dropping bombs and people are dying. In russia 2 people means 20. 10, 100. So understand that when the reports say 5 people got killed. Submarines, s400, cruise missile and icbm factories all have been blowing up.