There is probably some gouging going on but it is hard to tell how much because of complications in the system. Oil companies have tailored refinery capacity to demand so when there are glitches the supply system or big changes in demand there are big price swings. Politicians didn't get rid of the refineries, oil companies did. Why spend a bunch more on refineries just to flood the market, make your products cheaper and reduce your profits? The lower mainland used to have four refineries, now it has one and BC only refines 48% of what it uses, the rest is shipped from Alberta and the US.
The US is also experiencing its highest gas prices in seven years. While the difference in gas prices is usually quite high, because of US tax structures the price of diesel us usually much closer, sometimes even cheaper in Canada than some US states. Oil is priced in USD so when our dollar drops, we pay more for oil and also gas that is not refined in Canada. GST also compounds things because it is charged on the after tax price of the gas. When it comes to gas and diesel, it is a tax on a tax.