Copypasta my other comment:
The bulk of Canadian exports to the US are oil. We can certainly tariff US goods, but export tariffs on Canadian oil and hydro electricity to the US will probably be a big component of the Canadian response.
Even with a big increase on hydro power exports to the US, it's still cheaper than most other sources of electricity, so they'll still happily pay it.
As to oil, there are some refineries in the US that are set up to process Canadian bitumen. Canada's long history of just exporting raw materials and re-importing finished goods give a pretty outsized room to manuever here. This refineries will probably just pony up and pay more.
Where the damage will come is in areas like the auto sector, where there are tightly coupled supply chains.
Paul Krugman points out in his article The End of North America that there is probably already damage done to the concept of North American manufacturing.
Trump is going to do a whole lot of damage, we're going to take some of that damage, but my favourite quote on the topic:
no one wins trade wars, but the kid who never stands up for himself always loses and for a long time
There are a few of causes for hope.
First, Trump has surrounded himself with loyalists and sycophants, not competence. On the downside, this is how Putin ended up on year 3 of a 3-day "special military operation" in Ukraine. Trump is going to make incredibly stupid mistakes not just because he's stupid, but everyone he has surrounded himself with will be telling him how wonderful and clever he is. On the other hand, this is a good way to get clobbered by reality.
Canada and Mexico have responded with targeted tariffs and are also planning ahead to next steps. Heck, Canada just finalized a trade deal with Ecuador. Sure it's not going to replace the US, but it shows many competent people are out there working for Canada. Meanwhile the US government apparatus is going to be gutted of competent people.
Second, Canada does export a lot of raw materials, which should be easier to shift to other markets. Also things like hydo power and oil can probably absorb a fairly high increase in cost without being substantially effected. Hydro power as an example, can easily eat a 10% increase and still be the cheapest source of electricity. Canada could probably slap export tariffs on oil, hydro electricity, and potash and the US will just have to eat it.
Finally, Trump will probably continue tariffing the EU and other countries as well, further triggering retaliatory tariffs. This means Bosch, Samsung and LG will need to make more dishwashers to replace the Whirlpool and Maytag dishwashers that aren't going to be sold outside the US (as an example). It's going to suck, but Canada already has CETA and CPTPP to build on, and should be deepening CANZUK ties. The world is bigger than the US, and the US looks set to isolate themselves from everyone. Being on the outside in that case is better.