Below minus forty

Cold snap, you say? I do remember one New Year’s Day when the temperature in the Moscow region dropped below −40°. (Celsius or Fahrenheit? In this particular case, it’s the same: −40 °C = −40 °F = 233.15 K.) On 1 January 1979, we woke up in the (late) morning only to discover that we are stuck without any tea or hot food. We couldn’t switch on the gas cooker, which was running on propane/butane mixture. Why? As explained in this useful guide,

When the temperature of the liquids falls below its current boiling point the pressure inside the canister will no longer drive vapour out.

The boiling point of butane is −0.5 °C and that of propane is −42 °C; the temperature outside was below −42 °C, and the gas canisters were outside!

My mum called for a friendly neighbour who was better equipped than us. We kids did not worry too much about a guy warming up a gas canister with a blow torch. Anyway, everything went just fine and we had a wonderful day.