Here is one pretty critical detail that was not mentioned -
This last summer a expedition from the Scientific Center of Arctic Studies found methane concentrations of 9.6% at the bottom of the crater – 50,000 times the atmospheric average.
The possibility that methane released by melting permafrost produced the crater had been a favored hypothesis from its discovery in mid-July.
Wow. 9.6% is smack in them middle of BOOM!
https://www.mathesongas.com/pdfs/products/Lower-(LEL)-&-Upper-(UEL)-Explosive-Limits-.pdf