OK, first off Natural Gas is predominantly Methane and is still cheap even with the cold snap.
Propane however is a product of gasoline refining and is directly tied to the price of oil. They get only a tiny fraction from each barrel and it is not made in near unlimited quantities as those who converted from fuel oil to propane "to save money" are finding out this year.
Propane is hard to "bank" (store) in large quantities and so some is "flared off" at refineries (along with other gases) when there is no place to store it. This year is not normal and usage has exceeded expectation.
Since it has a fixed fraction, propane manufacture is limited to the barrels of oil refined.
Price is set by supply and demand. Supply is relatively fixed so as demand increases, price does too.
You might want to think this is a "great conspiracy" but in reality, the law of supply and demand is just that: A law of human nature.
If a thing is free, there is never enough as people will waste it till it is all gone. If a thing is "dear", they will conserve it and find ways to use it efficiently.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW