Indeed, according to the Globe and Mail the hit to oil supplies taken is equivalent to losing an entire Canada's worth of crude.
Simply put, it's enough to hurt a lot more than just the oil companies in the US and despite what people wish for, the US economy is still intricately tied into the global one.
Speaking as a Canadian, our gas prices jumped up to 20 cents Canadian per liter this weekend. That's about 75 cents US per gallon.
In any case, the reserves were set up for if oil shortages would have large economic ramifications and I think that applies to the current situation (albeit it's too early since not all the damage reports have come in and been reported).